Full opinion text
OPINION GOETTEL, District Judge. I think that I shall never see a lawsuit as lovely as a tree. One may well wonder whether this would have been the opening of Joyce Kilmer’s poem had his experience with trees included an intimate association with this case. While trees may indeed make lovely poems, they lose some of their aesthetic appeal when made the subject of litigation. We return to the continuing saga of the County of Westchester’s efforts to clear the airspace over property owned by several landowners on the Connecticut side of the border separating New York from Connecticut. Reduced to its simplest terms, this case represents the proverbial struggle matching commerce against nature, airplanes against trees. I. FACTUAL BACKGROUND While the background of this case has been outlined in previous opinions, see 745 F.Supp. 951 (S.D.N.Y.1990) and 756 F.Supp. 154 (S.D.N.Y.1991), we shall detail the material facts so that our decision may be understood by those unfamiliar with the ongoing trials and tribulations of the West-chester County Airport. Plaintiff, the County of Westchester, located in the State of New York, owns and operates the Westchester County Airport (“WCA”) which abuts the border between New York and Connecticut. Defendants are all residents of Connecticut who own parcels of land on the Connecticut side of the border situated on or near the state line. The airport began operations more than forty years ago and is presently used by both private and commercial aircraft. It has developed into a busy regional airport servicing the air transportation needs of both New York and Connecticut residents. The WCA currently utilizes two runways. Runway 16/34, the airport’s primary runway, runs in a roughly northeast-southwestern direction for 6550 feet. Runway 11/29, the alternative runway embroiled in this dispute, is a 4450 foot long landing strip without an instrument landing approach, angled in a roughly east-west direction. Runway 11/29 is sandwiched between Interstate Highway 684 and Rye Lake on its western end and the Connecticut border on its eastern end. It is usually used only when the prevailing crosswinds make use of the main runway too dangerous for all but the largest classes of aircraft or during an emergency. Since the opening of the airport, runway 11/29 has been used frequently, ranging from as few as a dozen flights up to sometimes 80 flights per day. The controversies in this case are, quite literally, rooted in the southeastern end of runway 11/29 fronting the New York-Connecticut border. Like all airstrips, runway 11/29 has an approach zone of airspace stretching out from its ends. On its southeastern end, runway 11/29, rather unfortunately, has an air approach located almost entirely in Connecticut. Accompanying the actual flight path used by airplanes while taking off and landing, the Federal Aviation Administration (“FAA”) requires that buffers of airspace, known as “clear zones,” exist above certain imaginary surfaces. The FAA has determined that safe operation of airplanes requires that areas above these surfaces be kept clear of obstructions. See Flowers Mill Associates v. United States, 23 Cl.Ct. 182 (1991). FAA regulations specifically define two types of clear zones that are significant for this case: a trapezoidal-shaped “approach surface” beginning from a point 200 feet beyond the end of the runway and extending outward for a distance of 5,200 feet at a slope of one foot vertical rise for each 20 feet in horizontal distance (20:1), see 14 C.F.R. § 77.25(d), and a supplemental “transitional surface” rising from each side of the approach zone at a slope of one foot of vertical rise for every 7 feet of horizontal rise (7:1). See 14 C.F.R. § 77.25(e). The land underneath this airspace is owned by the various defendants, the Town of Greenwich, the Laurelton Nursing Home, Inc., the Convent of the Sacred Heart, Greenwich King Street Associates II, L.P., and Mildred Tomonto. Defendants’ lands are filled with trees that over the years have, not surprisingly, been growing. Over time, an increasing number of trees located on the defendants’ properties have grown into runway 11/29’s clear zones eventually forcing aircraft using this runway to dramatically alter their landing patterns. Documentation of this growth has been uneven. Testimony from pilots and a 1948 color photograph of the area show the existence of vacant fields with identifiable lines of trees along property boundaries and King Street, as well as clusters of trees on the Convent’s property. The National Oceanographic and Atmospheric Administration (“NOAA”), a federal agency, has periodically surveyed runway 11/29’s obstructions between 1949 and 1990 and produced official charts of the clear zones. The 1950 NOAA chart shows two, possibly three, trees penetrating runway 11/29’s 20:1 clear zone. In 1964, the NOAA chart shows 5 trees encroaching on the approach surface and 3 trees in the transitional surface. In 1970, NOAA individually identified 5 trees above the approach surface and 3 trees breaking the transitional surface. The 1970 chart also documented wooded areas within the clear zones along the entire length of King Street, falling within the 20:1 clear zone as well as three larger wooded areas inside the 7:1 transitional zone. By 1982, NOAA separately identified 4 trees inside the 20:1 approach zone and 5 trees within the 7:1 transitional zone. Again, the 1982 chart noted wooded areas along nearly the entire length of King Street and also penetrating the left edge of the 20:1 approach zone. Also, significantly larger clusters of trees existed in the transitional clear zone bordering the left side of the 20:1 approach zone. In 1984, the WCA contracted with a surveyor to determine the precise heights of obstructions to runway 11/29’s clear zones using photogrammetric analysis. The results of the 1984 Donnelly survey show some 125 trees penetrating runway 11/29’s clear zones. In 1990, Donnelly was again commissioned to survey the clear zones and documented some 128 trees inside the clear zones of which 55 were penetrating the 20:1 clear zone. There were also an additional 6 trees whose tops were broken but which had penetrated the clear zones in 1984. In sum, the number of trees encroaching on runway 11/29’s clear zones has increased significantly over the past forty-two years. ■ The changes in the land use have varied to some degree by defendant. Greenwich King Street Associates, a limited partnership, owns some 152 acres of property which has witnessed the most dramatic growth. What was primarily fields lined with a row of trees in 1948, before it purchased the property, has been transformed into a maturing forest. Photographic evidence seems to indicate that a portion of King Street Associate’s land had been used as a tree nursery for an uncertain period of time beginning in the 1960s, before King Street Associates acquired it. The nursery was subsequently abandoned and apparently many of the trees were left to grow wild. King Street Associate’s property lies directly adjacent to the airport and underneath runway 11/29’s center line. In 1989, the County proposed to remove or top infringing trees at its own expense while covering the cost of any landscaping necessary, but nothing ever came of the offer. Defendant Laurelton Nursing Home’s property contains fewer trees intruding on runway 11/29’s clear zones, primarily concentrated near the intersection of the primary and transitional zones near the northern border of the property. Plaintiff notes that defendant Laurelton Nursing Home was required to get approval, which it did, from the FAA as. a condition precedent to its construction of the nursing home. Defendant Mildred Tomonto’s property also contains fewer intrusive trees by comparison than exist on Greenwich King Street Associates’ land. Tomonto’s trees are located immediately adjacent to the airport, on the north side of the land near the Tomonto house, and along its boundary with the Laurelton Nursing Home. While fewer in number, the Tomonto trees are disproportionately problematic because they are growing near runway 11/29’s center line. In 1989, the WCA requested permission of Tomonto to enter her property to cut down certain trees inside the clear zones. The WCA maintains that it received no response from Ms. Tomonto, interpreting this as a rejection of its offer. The Town of Greenwich, in its management of King Street as a public thoroughfare, has assumed responsibility for maintenance of the trees lining King Street. King Street traverses the entire width of the 20:1 clear zone crossing runway 11/29’s center line some 1200 feet from the end of the runway. Its trees have grown substantially over the years. In 1963, the Town’s Planning and Zoning Commission adopted a Land Use Plan of Development that included the Commission’s proposal to control the use of land within the WCA’s clear zones to “prevent the erection of structures within them.” The Plan was a statement of land use objectives that carried with it no direct effect on land use within Greenwich. Its implementation depended upon actions by other Town agencies and the willingness of property owners in developing their lands in conformance with the plan. The WCA’s clear zones, however, have been factored into the zoning and construction permitting process of the Town of Greenwich. In December 1963, the Town’s Planning and Zoning Commission recommended the denial of defendant Laurelton Nursing Home’s application to build a nursing home adjacent to King Street specifically because of its safety concerns over locating the proposed building within one of the WCA’s runway clear zones. In 1975, the Town’s Planning and Zoning Board of Appeals denied an appeal for a zoning variance that would have permitted the start of a tree surgery business and the parking of road equipment on the western side of King Street. The Board found that the applicants were not uniquely burdened by the WCA since the airport was a common burden on all that area’s property owners. On April 27, 1987, the Board denied an appeal by Greenwich King Street Associates I, L.P. to erect an office building on the east side of King Street. Again, the Board concluded that the hardship on the applicant caused by the neighboring airport was a common burden on all property owners in the area and did not justify a unique hardship variance to the zoning regulations. Compared to the other defendants, the property belonging to defendant Convent of the Sacred Heart is set furthest from runway 11/29. The bulk of the Convent’s trees penetrating the clear zones are located near the Convent’s main building. Many of these trees existed when the WCA first opened, although many others are newer. A number of them stand under runway 11/29’s center line, and like those lining King Street, can partially block a pilot’s view of the runway during a final approach. The Convent’s trees have seen substantial growth. The Convent admits that it has maintained and nurtured its trees over the years and desired its trees along King Street to provide screening from the airport. Information concerning tree intrusions into runway 11/29’s clear zones was first brought to the WCA’s attention as early as 1969. In March 1981, after conducting on site inspections of the airport, the FAA informed the WCA by letter that tree obstructions were observed in the clear zones and approaches to runway 11/29. The FAA requested the WCA to initiate action to remove the obstructive trees. Three months later, the FAA reiterated its position regarding the removal of trees within runway 11/29’s clear zones and recommended displacement of the runway landing threshold if removal was not possible. The FAA’s attention to runway 11/29 resurfaced in September 1984 when it requested that the WCA document all penetrations of its clear zones and provide a scheduled plan of action for the removal of any obstructions, or displace the runway threshold. The FAA set a December 1984 deadline for receipt of the information. The WCA responded in October 1984 advising the FAA that it had issued a “notice to airmen” or “NOTAM” advising pilots to use steeper descents when approaching runway 11/29 in order to clear the trees blocking the clear zones. The WCA also informed the FAA that an aerial survey had been conducted and was being charted. The preliminary results were that some 79 trees in Connecticut currently encroached upon the clear zones. The WCA concluded that it was researching its legal options and would incorporate the NOAA’s obstruction chart findings into its study. Again in early February 1985, the FAA contacted the WCA asking for an evaluation of the latest obstruction chart produced by the NOAA, a plan of action, and a timetable for disposing of each obstruction. The FAA reset the deadline to February 28, 1985. Apparently venting frustration with the WCA’s lack of progress, the FAA sent a terse letter in May 1985 stating that prompt action in the form of tree removal or runway displacement was necessary since the tree penetrations into runway 11/29’s clear zones were substantial and hazardous. The dialogue between the FAA and the WCA continued through 1989. Another FAA warning was communicated to the WCA in October 1988 stating that immediate action was required to remove the multiple intrusions into runway 11/29’s clear zones that threatened the safety of landing aircraft. The FAA warned that if the trees were not removed or topped by the end of October 1988, it would order the displacement the runway’s landing threshold. True to its promise, in February 1989, the FAA ordered runway 11/29’s landing threshold to be displaced, effectively shortening the usable runway by some 1300 feet. Some time later, the Connecticut property owners rejected an offer by the County to trim the trees back to an acceptable height at the County’s expense. The County projects that by the year 2000, the runway will require a displacement of some 1700 feet, a loss severe enough to possibly shut down runway 11/29. In February 1990, the County of West-chester instituted an action for declaratory and injunctive relief against the Town of Greenwich, the Commissioner of Transportation for the State of Connecticut, Laurel-ton Nursing Some, Greenwich King Street Associates II, the Convent of the Sacred Heart, and Mildred Tomonto. In an earlier decision, this court dismissed plaintiff’s state law cause of action against the Commissioner of Transportation of the State of Connecticut holding that the Eleventh Amendment to the United States Constitution prohibited such suits. The court also dismissed plaintiff’s claims against the remaining defendants under the interstate commerce clause of the Constitution, the Federal Aviation Act, and public nuisance under Connecticut’s statutory law. The County has three remaining causes of action before this court: prescriptive easement, common law nuisance, and equitable servitude. First, the County contends that under Connecticut law it has acquired a prescriptive easement over the airspace used to navigate landings and takeoffs from runway 11/29 through its use over the past forty or more years. According to the County, this corridor of airspace approaching runway 11/29 has existed and been used without any material obstructions from 1945 up through the early 1970s. This airspace, argues plaintiff, is located directly above the imaginary surfaces specified by the FAA and provides a safety buffer of air between the flight path and the- nearest object on the surface. Plaintiff argues that by flying through its approach paths it has used this corridor of airspace — what it terms clear zones — as a safety buffer for purposes of acquiring a prescriptive easement. Defendants offer several arguments in response. At base, they argue that the County can point to no fifteen-year period during which planes used the approach to runway 11/29 with its clear zones devoid of trees. Indeed, defendants contend that trees have penetrated the clear zones since 1949 and in significant numbers at least since 1970 when they extended across the primary zone. Defendants further argue that the County’s conduct belies any notion that it was acting under a claim of right. The County repeatedly attempted to secure permission from the landowners to trim the troublesome trees and generally failed to act in a manner which put defendants on notice of their use of the clear zones as a claim of right. Citing Connecticut laws on easements, they also stress that prescriptive easements may only extend to those portions of another’s property that have been actually or physically used. In their view, the County can acquire a prescriptive easement under Connecticut law only over the airspace in which its planes actually flew, provided it meets the other easement requirements, something defendants strongly contest. Since no planes continuously flew through the clear zones (as contrasted to flight paths) for a fifteen year period, no prescriptive easement to this airspace ever matured. Even assuming that the County secured a prescriptive easement over the clear zones, defendants claim to have regained their rights to this airspace by reoccupying the clear zones with their trees for more than fifteen years, in essence supplanting any easement the County may have secured with a subsequent prescriptive easement of their own. Defendants also claim that the use of the clear zones airspace for trees is both reasonable and lawful as a matter of law, precluding any finding of a nuisance. In their view, locating a runway adjacent to a wooded, suburban, residential property was the unreasonable action, not the growing of trees. Granting the County its easement, says defendants, will force the clearing of trees down to such low airspaces as to unreasonably restrict the defendants’ use of their properties. Moreover, they argue, given the County’s actual knowledge of the tree obstructions since 1969, its persistent inaction prevents it from seeking its equitable relief now under the doctrine of laches. II. DISCUSSION Plaintiff and all of the remaining defendants have moved for summary judgment on the claims of prescriptive easement, public nuisance, and equitable servitude, each arguing that no material facts exist to preclude this court from ruling on the issues as a matter of law. The standards for summary judgment are firmly rooted in our legal landscape. To prevail, the moving party must demonstrate “that there is no genuine issue as to any material fact and that [it] is entitled to a judgment as a matter of law.” Fed.R.Civ.P. 56(c). Material facts are those facts that “might affect the outcome of the suit under the governing law ... [fjactual disputes that are irrelevant or unnecessary will not be counted.” Anderson v. Liberty Lobby, 477 U.S. 242, 248, 106 S.Ct. 2505, 2510, 91 L.Ed.2d 202 (1986). A dispute over a material fact is genuine “if the evidence is such that a reasonable jury could return a verdict for the nonmoving party.” Id. All parties in this case contend that the evidence presented leaves no materials facts in dispute. The court must resolve all ambiguities and draw all inferences in favor of the party defending against the motion. Eastway Const. Corp. v. City of New York, 762 F.2d 243, 249 (2d Cir.1985), cert. denied, 484 U.S. 918, 108 S.Ct. 269, 98 L.Ed.2d 226 (1987). Uncertainty regarding the true state of any material fact will defeat a summary judgment motion. United States v. One Tintoretto Painting Entitled “The Holy Family With St. Catherine and Honored Donor”, 691 F.2d 603, 606 (2d Cir.1982). The County of Westchester claims that it is entitled to the unobstructed use of runway 11/29 including the clear zones which accompany its use. In response, defendants contend that the County has not established any easements, and even if so, defendants have regained by prescription an easement giving their trees the right to continued upward mobility. This court previously held that the County’s causes of action are rooted in Connecticut law. County of Westchester v. Town of Greenwich, 745 F.Supp. 951, 957 n. 7 (S.D.N.Y.1990). It is under this canopy of law that we shall attempt to resolve these issues. A. The Common Sun, The Air, The Skies : Federal Law on Airspace Although this court previously held that federal regulation of the nation’s airspace provides no foundation for a cause of action by the County, we shall outline the federal law on airspace which stands as a backdrop for our decision. The navigable airspace of the United States has been incorporated into the public domain. See City of Oakland v. Nutter, 13 Cal.App.3d 752, 92 Cal.Rptr. 347 (1st Dist.1970) (citing cases); Shipp v. Louisville & Jefferson County Air Bd., 431 S.W.2d 867, 870 (Ky.1968), cert. denied, 393 U.S. 1088, 89 S.Ct. 880, 21 L.Ed.2d 782 (1969). Congress, expressing its sovereignty over the nation’s navigable airspace, has recognized “a public right of freedom of transit through the navigable airspace of the United States.” 49 U.S.C.App. § 1304. “Navigable airspace” is defined as: airspace above the minimum altitudes of flight prescribed by regulations issued under this chapter, and shall include airspace needed to insure safety in take-off and landing of aircraft. 49 U.S.C. § 1301(24). This navigable airspace extends down to an imaginary surface 50 feet above the surface of defendants’ lands. See 14 C.F.R. § 151.9(b). Effectively, federal law has pruned the bundle of property rights held by surface landowners rather than uprooted it in its entirety. They retain the right to the use and enjoyment of their land including the immediate airspace that can be reasonably used. “We own so much of the space above the ground as we can occupy or make use of, in connection with the enjoyment of our land. This right is not fixed. It varies with our varying needs.” Allegheny Airlines, Inc. v. Village of Cedarhurst, 132 F.Supp. 871, 879 (E.D.N.Y.1955), aff'd, 238 F.2d 812 (2d Cir.1956) (quoting Hinman v. Pacific Air Transport, 84 F.2d 755, 758 (9th Cir.1936)); see also Jackson Municipal Airport Authority v. Evans, 191 So.2d 126 (Miss.1966); Mills v. Oreas Power & Light Co., 56 Wash.2d 807, 355 P.2d 781 (1960). Low altitude flights which unreasonably interfere with the use and enjoyment of the land represent a trespass or partial taking creating a right to compensation. See United States v. Causby, 328 U.S. 256, 66 S.Ct. 1062, 90 L.Ed. 1206 (1946). As the Court stated in Causby: The airspace, apart from the immediate reaches above the land, is part of the public domain. , We need not determine at this time what those precise limits are. Flights over private land are not a taking, unless they are so low and so frequent as to be a direct and immediate interference with the enjoyment and use of the land. Id. at 266, 66 S.Ct. at 1068. Even when such flights fall within the navigable airspace, and therefore use of this low altitude airspace is authorized, compensation is still required for the taking. See Griggs v. County of Allegheny, 369 U.S. 84, 88-89, 82 S.Ct. 531, 533, 7 L.Ed.2d 585 (1962). This ease is unique, largely because the airport seeking easements is located in a different state from the adjacent landowners whose airspace is at issue. We previously held that FAA regulations furnish no basis for the County to compel the removal of the trees. County of Westchester, 745 F.Supp. at 955-57. The County, powerless to exercise eminent domain over property across the state line, was forced to resort to remedies provided under Connecticut law. Thus, we must turn to the question of what rights and remedies exist for the parties under Connecticut law concerning the airspace immediately above defendants’ properties. B. Flying Chariots Through Fields Of Air : Prescriptive Easements Connecticut law on prescriptive easements is clear, Be it flying machines or growing trees, to show the existence of an easement by prescription a person must show use that is open, visible, continuous, uninterrupted, and adverse, made under a claim of right for a period of fifteen years. Klar Crest Realty, Inc. v. Rajon Realty Corp., 190 Conn. 163, 459 A.2d 1021 (1983); McCullough v. Waterfront Park Ass’n, Inc., 1992 WL 24332, 1992 Conn.Super. LEXIS 240 (Conn.Sup.Ct.1992); see also Conn.Gen.Stat.Ann. § 47-37 (West 1988) (requiring fifteen years of continuous, uninterrupted use for easements). The term “under claim of right” means “without recognition of the rights of the owner of the servient estate.” Andrejczyk v. Advo System, Inc., 146 Conn. 428, 151 A.2d 881, 883 (1959). A prescriptive easement is valid only if its boundaries can be determined with reasonable certainty. See Reynolds v. Soffer, 190 Conn. 184, 459 A.2d 1027 (1983); Keiko v. Dolinger, 184 Conn. 509, 440 A.2d 198 (1981). The County maintains that it has acquired such an easement over a corridor of airspace through which planes using runway 11/29 navigate, airspace that includes the so-called clear zones. At the outset, we must be clear as to the nature of the easements being contested. The County has the tendency to speak of its rights as encompassed within a single easement. Defendants correspondingly maintain that the existence of trees inside the clear zones since the airport’s opening undercuts the County’s easement claim entirely in one fell swoop. Although the core of the County’s claim seems to be its right to remove defendants’ trees from the clear zones, its claim represents a combination of rights of usage encompassing two separate easements. The County asserts an avigation or flight easement giving it a right to fly through the airspace above defendants’ properties. Concurrently, it seeks a clearance easement providing it the right to cut down those trees obstructing the approach to runway 11/29 and its clear zones. These two easements are distinct. See United States v. Brondum, 272 F.2d 642, 644-45 (5th Cir.1959) (distinguishing avigation from clearance easements); United States v. 64.88 Acres of Land, 244 F.2d 534, 535-36 (3rd Cir.1957); see also City of Oakland v. Nutter, 13 Cal.App.3d at 763, 92 Cal.Rptr. 347. The purpose of avigation easements is to allow aircraft to fly through a given airspace. The function of the clearance easement, likened to a ceiling, is: to increase the margin of safety for flying by assuring that the glide zone will be free from natural growth or man-made obstructions and the pilot’s vision unobscured above a designated altitude. City of Oakland v. Nutter, 13 Cal.App.3d at 763, 92 Cal.Rptr. 347. From the tenor of its arguments, it is apparent that the County seeks recognition of both types of easements. First, it seeks an avigation easement over the glide path for runway 11/29 that aircraft used before the trees forced significant changes in flight paths. Second, the County seeks a clearance easement allowing it to remove, or at least top, trees encroaching upon the airspace located within runway 11/29’s clear zones, airspace located between the lower limits of the navigable airspace and the upper limits of usable airspace above defendants’ lands. C. Objects In An Airy Height : Existence of Easements Under Connecticut Law Before determining whether the County has met the requirements of establishing a prescriptive avigation or clearance easement for runway 11/29’s clear zones, our initial inquiry is whether such easements are even cognizable under Connecticut law. 1. The Avigation Easement It appears that Connecticut courts have yet to reach the question of whether avigation easements may be acquired by prescription. Among the few jurisdictions that have addressed this issue, there is general disagreement over whether an avi-gation easement may be acquired by prescription. While not deciding the existence of a prescriptive avigation easement on the facts before it, the California Court of Appeals has stated that it saw “no reason why an avigation easement may not be acquired by prescription in this state.” Drennen v. County of Ventura, 38 Cal.App.3d 84, 87 n. 2, 112 Cal.Rptr. 907 (2nd Dist.1974). The court in Petersen v. Port of Seattle, 94 Wash.2d 479, 618 P.2d 67 (1980), while also concluding that no such easement had been evidenced, similarly recognized the existence of prescriptive avigation easements. See id. 618 P.2d at 70-71. The Supreme Court of Appeals for West Virginia, however, reached a contrary conclusion. Emphasizing the practical difficulties in recognizing and defining prescriptive avigation easements, the court in Sticklen v. Kittle, 168 W.Va. 147, 287 S.E.2d 148 (1981), held that prescriptive easements of avigation did not exist. The court voiced its concern that changes in the types and frequency of overflying aircraft, multiple flight patterns, and overflights of several different tracts of land create intractable problems in defining the boundaries and uses of a particular avigation easement. See id. at 155, 287 S.E.2d 148. While the status of an avigation easement under Connecticut is unfixed at present, we are persuaded that recognition of a prescriptive avigation easement is the proper course. As we stated in an earlier opinion, it stands to reason that if overflights are considered a definite enough act to form the basis of a constitutional takings claim, such activity should be considered tangible enough to form the basis of a prescriptive easement. See County of Westchester v. Town of Greenwich, 745 F.Supp. at 961. Whether a party’s actions sufficiently establish an easement’s boundaries with a reasonable degree a certainty would generally be a question of fact requiring resolution by the trier of fact. 2. The Clearance Easement Determining the status of clearance easements under Connecticut law is a more difficult task. It has been stated as a general proposition that negative easements, easements preventing someone from using a given property, cannot be established by prescription “because the claimant of such an easement does not become subject to legal action at the hands of the owner of the potential servient estate by engaging in the conduct appropriate to establish such an easement.” Classen v. State, Dept. of Highways, 621 P.2d 15, 18 (Alaska 1980) (quoting 3 R. Powell, The Law of Real Property II413, at 34-119 (Rohen rev. ed. 1979)). Clearance easements would seem to fall in this category, essentially representing a right to prevent surface landowners from using certain airspace. Underlying this general rule is the notion that an airport seeking a clearance easement cannot satisfy the requirements that its use be adverse, open, visible, and actual. Defendants contend that use of a clear zone, by definition an empty zone of airspace absent some emergency, cannot be an open and visible use which constitutes an action adverse to the owner’s rights to the airspace giving it knowledge and opportunity to asserts its own property rights in opposition. See Aksomitas v. The South End Realty Co., 136 Conn. 277, 70 A.2d 552, 554 (1949) (“[U]se must be so open, visible, and notorious as to give the owner knowledge and a full opportunity to assert his own rights.”). Thus, the argument goes, no prescriptive clearance easements can develop as a matter of law. We have been unable to find any Connecticut authority directly addressing whether clearance easements may be acquired by prescription. The possibility of establishing a clearance easement to airspace by prescription has been implicitly recognized in other jurisdictions. See, e.g., Shipp, 431 S.W.2d at 870. Connecticut courts, however, have discussed other types of use, beneficial to the public, which do not seem to meet, on their face, the requirements of an actual physical use. The court in American Trading Real Estate Properties, Inc. v. Town of Trumbull, 215 Conn. 68, 574 A.2d 796 (1990), addressed the notion of “actual public use” when an adverse possession claim is made against a town. The Connecticut Supreme Court found that limiting the definition of public use to physical uses only was unduly narrow. American Trading, 574 A.2d at 801-02. The court discussed a town’s use of a buffer of undeveloped property to protect a park from encroaching development. It also imagined the use of open space or undisturbed land to protect communities, wildlife, or wetlands. Id. Recognition of such nonphysical uses was deemed necessary to protect the existence of highly beneficial public interests like the environment. Other courts have also viewed the concept of actual use as encompassing more than simply what is physically occupied. See, e.g., Platt v. Ingham County Road Commission, 40 Mich.App. 438, 440, 198 N.W.2d 893 (Ct.App.1972) (“Since a right-of-way is deemed to encompass such use of the land at or beneath the surface as will make the easement effective, a similar concept of use must be employed in determining ‘actual use.’ ”). Protecting the ability of aircraft to use the WCA’s runway 11/29 requires recognition of an analogous buffer of unused airspace. Safeguarding the passage of aircraft over populated areas is obviously of paramount concern to the County, and presumably to Connecticut as well. The Commissioner of Transportation for Connecticut has to date shown no interest protecting its citizens, who use the WCA in significant numbers, by removing the trees from runway 11/29’s clear zones. The Commissioner is apparently empowered by statute to require owners of any obstacles constituting a hazard to aerial navigation to remove those obstacles. While it is by no means clear, we conclude that Connecticut law would recognize the establishment of a clearance easement by prescription. Connecticut recognizes certain non-physical uses of land when they serve important, even vital, public needs. Moreover, in the case of airspace, federal regulations specifically define the existence of such zones of airspace. The public is on general notice that aircraft passing overhead maintain their safe passage by relying upon clear zones underneath their glide paths. Under these circumstances, to insure the safe use of these flight paths, we conclude that clearance easements to such airspace can be acquired by prescription. D. Saw The Heavens Fill With Commerce : Establishment of an Avigation Easement Given their legal existence, the question remains whether the County’s use of runway 11/29 meets the requirements for establishing a prescriptive easement over the airspace needed for its flight paths and clear zones. In assessing the County’s claims, we shall treat the prescriptive easement requirements as falling within two broader categories. The first grouping of easement criteria define the physical nature of the use that places an owner on notice. These notice-oriented criteria include the requirements of adverse, open, and visible use under a claim of right. The second set of criteria address the more temporal aspects of easements, that is the requirements of continuous, uninterrupted use for at least fifteen years. 1. Cannot See The Glide Path For The Trees?: The Notice Criteria For Easements We begin by addressing the County’s prescriptive avigation easement claim. The County is seeking to reestablish its ability to use the glide path for runway 11/29 that aircraft had used until defendants’ trees forced planes to substantially adjust their takeoff and landing patterns. We shall confine our analysis here to the airspace actually used by the County for its approach path to runway 11/29, namely the airspace that aircraft flew through. We first examine the first branch of the easement criteria, the open, visible, and adverse requirements for a prescriptive easement. We have no trouble concluding that the County’s use of the glide paths was open and visible. Aircraft regularly passing overhead during their landings and takeoffs are hard to miss. And defendants have offered no evidence that any Stealth fighters operated on runway 11/29 or that any of the aircraft used the infamous Rom-ulan cloaking device. For the clearance easement sought by the County, defendants contend that the County cannot show that use of clear zones, which are essentially empty airspac-es, can be open, visible, or adverse. While this position carries a certain common sen-sical force, we do not reach the same legal conclusion. Although clear zones are at base a buffer of unobstructed airspace between an airplane and the top of any surface obstructions, this does not mean by definition that the open and visible easement requirements cannot be met. Defendants do not contend that they were unaware of the constant overflight of aircraft using runway 11/29 over the years. Anyone watching a plane pass overhead, besides seeing the basic flight path, would certainly see a buffer of airspace underneath the flight path separating the plane from the nearest obstacle. On occasion, particularly in foul weather, flights will drop below the prescribed glide path, making use of the safety buffer. On the issue of whether use of the glide path for the avigation easement was adverse, we reach a similar conclusion. The defendants’ properties lie beneath runway 11/29’s approach path. In the case of Greenwich King Street Associates, their land directly abuts the airport. Any conceivable take off or landing path must pass through airspace over these lands at altitudes low enough to be considered adverse. As defendants concede, the FAA-defined approach path lies at its lowest point within 31 feet of the surface of Tomonto’s property and 17 feet above Greenwich King Street Associates’ land. See Defendant To-monto’s Memorandum of Law at 3; Greenwich King Street Associate’s Memorandum of Law at 7. Aircraft passing at such low altitudes above defendants’ properties doubtless represent an adverse use. The County’s use of the airspace for flight paths and safety buffers is incompatible with the defendants’ desire to grow their trees in this airspace. Therefore, we conclude that the County’s use of runway 11/29’s flight path has been open, visible, and adverse. The question of adversity for the clearance easement is a more difficult issue. As with the avigation easement, aircraft following a 3-degree .glide path buffered by a clear zone lying above the FAA-defined 20:1 approach surface use airspace as close as 17 feet from the ground. At this range, there is no doubt that the County’s use of the clear zones as safety buffers is incompatible with defendants’ desire to grow trees of substantial height on their properties. Defendants also contend generally that the County failed to act under a claim of right. They argue that the County’s communications to defendants Tomonto and Greenwich King Street Associates requesting permission to enter their properties to trim obstructive trees shows an implicit recognition of defendants’ rights to the contested airspace. We disagree. “Use under a claim of right means ‘without recognition of the rights of the owner of the servient tenement.’ ” Wadsworth Realty Co. v. Sundberg, 165 Conn. 457, 464, 338 A.2d 470 (1973). Requesting permission to enter defendants’ properties in order to top trees does not belie plaintiff’s claim to have used the airspace under a claim of right. Asking permission to enter onto defendants’ grounds is different than seeking permission to enter the airspace. The former simply implies concern for avoiding a potential charge of trespassing; the latter act by the County would be tantamount to recognizing defendants’ right to the airspace, something the County has not done. 2. When The Bark Became Worse Than The Flight: The Temporal Easement Criteria We turn to the temporal easement requirements. Defendants’ primary contention is that no fifteen-year period exists during which time the clear zones were devoid of trees. This argument presumably runs against both types of easements sought by the County. Since planes were never able to fly unobstructed through the clear zones for any fifteen-year period, defendants conclude that the airport is unable as a matter of law to establish the requirement of continuous, uninterrupted use for an avigation easement. For the same reason, defendants contend that no clearance easement was acquired since trees have always occupied the 20:1 clear zone. Defendants are correct that some trees have occupied the 20:1 clear zone since the airport’s early days. The question is, however, whether plaintiff must show full command over the FAA-defined clear zones in their entirety to establish a prescriptive avigation to airspace above defendants’ properties. We think not. The linchpin of the County’s avigation easement claim is use of the glide path. If trees occupying the clear zones did not force aircraft to alter their approaches to runway 11/29, they have not defeated the County’s uninterrupted use of its approach path. Until the trees actually and substantially interfere with the County’s enjoyment of its flight easement, defendants have done nothing actionable for which the County could seek to enforce its flight easement. See Kelly v. Ivler, 187 Conn. 31, 450 A.2d 817 (1982) (stating that an obstruction to an easement is abatable if it materially or substantially interferes with the reasonable enjoyment of the easement). In short, defendants’ trees must obstruct the glide path enough to interrupt its use by the County. If trees did substantially obstruct the County’s use of the 3-degree glide path and clear zones after the County had 15 years of uninterrupted, continuous use, it must be determined whether any of the defendants reacquired use of this airspace through their own prescriptive easements. Usually, these questions of obstruction would be issues of fact to be resolved by the trier of fact. Here, however, both sides, referring to the series of NOAA charts and Donnelly surveys, argue that the material facts concerning tree growth in runway 11/29’s clear zones cannot be disputed, although each draws contrary conclusions from the evidence. Defendants highlight evidence that some trees existed within the 20:1 primary clear zone since 1949. The 1950 NOAA chart shows two, possibly three, trees penetrating the 20:1 clear zone along its outer edges on what appears to be the properties of King Street Associates and Tomonto. On the 1964 NOAA chart, five trees are individually identified which appear to penetrate the 20:1 approach zone, three along its outer sides between approximately 400 and 1000 feet from the end of runway 11/29, and two nearer to the runway’s cen-terline also standing approximately 500 and 1000 feet from the runway’s threshold. See Defendants’ Exhibits 1 and 2. The 1964 NOAA chart also shows wooded areas lying inside the 20:1 clear zone between 500 and 1500 feet from the runway. By 1970, however; the NOAA chart showed a wooded area extending across the width of the 20:1 clear zone. Russell Deposition at 274. This would have prevented approaching aircraft from using the airspace along the 20:1 approach surface. However, the 20:1 approach surface acts as a floor for the airspace available to approaching aircraft. As trees climb into the 20:1 clear zone, the cushion of airspace aircraft use for safety decreases. It is undisputed that trees have always existed inside the clear zones to some degree. This fact alone, however, does not undercut the County’s avigation easement claim. Nothing shows that trees interrupted an aircraft’s use of the 3-degree glide path or that any airplanes automatically adjusted their glide paths to steeper angles. When trees initially began to crowd the clear zones, some pilots chose to maintain their stabilized 3-degree glide path, flying nearer to the treetops instead of significantly altering their approach paths. See, e.g., Hughes Affidavit at 4. Since the mere existence of trees within the clear zones does not defeat the County’s easement claim, the crucial question becomes when did the trees begin to significantly impair the County’s ability to use runway 11/29. if the record indicates a dispute over this material question of fact, its resolution would have to await trial, and the summary judgment motions would be denied. The record, however, does not demonstrate such a dispute. When the troublesome trees were fewer and more isolated, they posed no significant problems for landing aircraft. Doak Affidavit at 9; Hughes Affidavit at 5-6; Lewis Affidavit at 6. During the earliest stages of tree growth in the clear zones, pilots during approach would add some power to momentarily level off the aircraft as they passed over the trees then resumed their descent at somewhat more than the 3-degree path. Doak Affidavit at 7; Watts Affidavit at 6. Pilots' have uniformly recounted that trees in the clear zones did not significantly obstruct the basic 3-degree approach which was practiced until the late 1970s or early 1980s, thirty or more years after the airport opened. .See, e.g., Clemow Affidavit at 4; Hughes Affidavit at 6; Lewis Affidavit at 4; Watts Affidavit at 6. At this point, pilots resorted to steeper approach paths to avoid the larger numbers of trees intruding into the 3-degree glide slope. See, e.g., Hughes Affidavit at 6; Lewis Affidavit at 5; Solimán Affidavit at 4; Watts Affidavit at 7. As one flight instructor put it when describing his teaching of approaches that sharply deviated from the normal 3-degree approach, “[pjarticularly in the later 1970s, no simulation was necessary since Runway 29 provided the abnormal conditions called for because of the tree growth.” Hughes Affidavit at 4. The record regarding the County’s use of the airspace over defendants’ properties is largely undisputed. All the evidence offered suggests that, since the WCA’s opening in the late 1940s, aircraft taking off and approaching runway 11/29 used a roughly -3-degree glide path. This use, unquestionably open and visible, was no less adverse and continuous for substantially more than 15 years. The progress of defendants' trees into the clear zones slowly forced aircraft to change their approach paths. Isolated trees penetrating the 20:1 clear zone between 1949 and 1964 caused pilots to make minor adjustments in their approach paths. Defendants argue that the growing numbers of trees inside the clear zones between 1949 and 1970 defeat the County’s claims of a fifteen-year period of uninterrupted use. As we noted earlier, this does not necessarily follow. The crucial issue is the exact point in time at which the trees began interfering with the County’s use of this airspace, causing aircraft to deviate from their normal 3-degree glide paths such that use would be considered interrupted. Plaintiff has offered undisputed evidence from pilot affidavits suggesting that this occurred at some time during the late 1970s. The NOAA charts and FAA correspondence offered by defendants do not themselves create a disputed issue of fact contradicting the pilots’ statements. The charts show scattered tree penetrations into the clear zones as early as 1949 which by 1970 formed a band extending across the width of the 20:1 clear zone, including certain trees reaching up to forty feet into the clear zones. Defendants infer from the charts that the trees interrupted the County’s use of runway 11/29’s approach path and clear zones by this time. On the record, the court, however, has no basis on which to say this inference can be reasonably drawn for the approach path. Trees clearly encroached upon the clear zones. However, this fact does not alone speak to the point in time when they interrupted the County’s use of runway 11/29’s glide path. Defendants have offered no evidence to show that County’s use of the 3-degree glide path for runway 11/29, the prescriptive period for which expired by the mid-1960s, suffered anything more than small deviations due to trees before the late 1970s. Defendants note the existence of a single tree, identified in a 1974 photograph, obstructing the 3-degree glide path for runway 11/29. This is not disputed by the pilots’ affidavits. Pilots did not deny making minor adjustments in their glide paths for tree growth prior to the late 1970s. What they-stated unequivocally, however, was that the trees did not significantly interfere with their 3-degree approach until the late 1970s. Even inferring that a single tree standing in the glide path in 1974 substantially obstructed its use, the County’s avigation easement would have matured some ten years earlier. While the County has offered clear evidence showing that tree growth posed substantial obstacles by the late 1970s, defendants have proffered no evidence showing that the trees which were in the clear zones by 1970 caused anything more than slight changes in approach to runway 11/29. Showing that trees reached into the clear zones by a given number of feet does not necessarily show that they altered the glide path of incoming or outgoing aircraft. The FAA warnings, prior to the early 1980s, noted penetrations into the clear zones. Again, however, this does not show whether aircraft were actually forced off their 3-degree glide path or not. Without more, defendants have not placed the moment of substantial interference with flight operations, and hence the easement requirement of uninterrupted use, for runway 11/29 into dispute. We conclude that the County has demonstrated a fifteen-period of open, visible, uninterrupted, and adverse use, beginning sometime in the late 1940s when the runway first opened for use and expiring at latest during the mid-1960s, sufficient to establish an avigation easement for the approach path of runway 11/29. 3. The Genus of Flight Easement Acquired Defendants suggest that any easement acquired by the County in an earlier age of flight would be based upon use significantly different from the use proposed today for runway 11/29, use which now includes jet aircraft. Under Connecticut law, “use” of a right-of-way easement “frequently involves the amount of traffic over the easement or alterations to the land to make it passable.” Center Drive-In Theatre, Inc. v. Derby, 166 Conn. 460, 465, 352 A.2d 304 (1974). Courts have found avigation easements lacking because the nature of the usage had changed so significantly that the easement proposed bore little resemblance to the easement previously acquired. In Petersen v. Port of Seattle, 618 P.2d 67, the court, while recognizing the existence of avigation easements, determined that the easement acquired was by much smaller aircraft making far fewer flights. Id. at 71. The facts here, however, suggest otherwise. Individuals associated with the operations of the WCA and pilots who have used runway 11/29 over the years state that the types of aircraft that used 11/29 in earlier periods, primarily lighter, small and medium-sized aircraft, are quite similar to those that used the runway in the 1970s, 1980s, and today in terms of rates of descent and flight characteristics. See, e.g., Clemow Affidavit at 2; Doak Affidavit at 2-5; Graber Affidavit at 6; Hornbech Affidavit at 3; Hughes Affidavit at 5; Lewis Affidavit at 3; Solimán Affidavit at 3; Watts Affidavit at 3-4. The County’s easement is likewise unaffected by major changes in the volume of aircraft operations. The only evidence offered on this subject shows that airport operations have not differed dramatically since the 1960s, except to the extent that total operations, after peaking in the late 1960s, have apparently retreated back to the levels prevalent in the early 1960s. Naturally, the number of daily flights using runway 11/29 varies with the day’s weather conditions and volume of air traffic. Graber Affidavit at 4. However, WCA personnel noted that overall airport operations have remained relatively constant over the years, with runway 11/29 representing an estimated 40% of the WCA’s operations. Id. Pilots have concurred, observing that runway 11/29’s use has been relatively constant between the 1950s and 1970s. See, e.g., Watts Affidavit at 4. When the wind conditions were appropriate, as many as 80 landings and takeoffs occurred daily on runway 11/29 from the 1950s through the 1970s. Id. One pilot stated that use of the runway dropped off slightly during the 1980s as interest in smaller private planes decreased. Id. However, airport personnel have said that use, although lower than in years past, remained constant from 1986 to the present. Russell Affidavit-at 4. This anecdotal evidence is supported by undisputed quantitative facts. In 1964, total airport operations numbered 202,129. They peaked in 1969 at 281,735 and dropped off to 255,232 by 1973. By the 1980s, total flights had leveled off with 203,271 in 1980 and 202,885 in 1984. Gra-ber Affidavit at 4. Based on this evidence, not contradicted by defendants, we must conclude that the volume of air traffic passing through runway 11/29’s approach path remained basically steady between 1960 and 1984, though peaking somewhat in the late 1960s. Thus, no evidence exists in the present record to support the notion that the avigation easement acquired by the County in the past would differ substantially from the easement desired by the County today. The nature of aircraft using runway 11/29, primarily smaller and lighter planes, has changed little over the years. There has been no showing that more than one approach path is used for runway 11/29. The advent of jet aircraft, a notable shift in the character of planes using the WCA, does not alter our conclusion that the easement sought by the County today does not materially differ from the avigation easement earlier acquired. Any easement established by the County during the 1960s would have followed the blossoming of jet aircraft in the 1950s. Their use would be included within the County’s easement. Moreover, pilots have stated that today’s jets are quieter than the earlier models using the WCA between 1960 and 1980. See Clemow at 2-3; Doak Affidavit at 5. Since current jet aircraft are less noisy than their predecessors, the avigation easement sought, less burdensome today on defendants than it had been in days past, more closely resembles the original easement that was established. Further, even if we assume that an easement for use of jet aircraft had not been originally established, such an evolution of the County’s avigation easement would have been established by the early 1980s, once the 15-year prescriptive period had run. Consequently, we conclude that the County’s avigation easement, acquired at the latest during the mid-1960s, is not markedly different from the easement proposed today. 4. Where The Easement Ends: Certainty of Boundaries Defendants further argue that the court cannot recognize the acquisition of any easements by the County because its use has not established their boundaries with any reasonable certainty. We conclude, however, that the avigation easement sought by the County has boundaries of reasonable degree of certainty. The typical approach to runway 11/29 begins from the traffic pattern altitude of 1500 feet above the ground. On final approach, pilots seek to maintain a constant descent along a 3-degree glide slope. Doak Affidavit at 7; Solimán Affidavit at 5. It was not until the late 1970s or early 1980s that the trees forced aircraft to deviate from their approach path in any significant way. See Clemow Affidavit at 4; Lewis Affidavit at 4. The record shows that, until the late 1970s, nothing more than minor variations existed in the 3-de-gree glide path used by aircraft landing on runway 11/29. Any avigation easement acquired by the County would have used airspace somewhere sitting on or slightly above a roughly 3-degree slope extending out from runway 11/29’s threshold. These parameters, with at most a few degrees of variation near the trees, are reasonably definite for purposes of defining the avigation easement associated with runway 11/29’s use. Given the constant, and during the winter months often heavy, use of runway 11/29, anyone living beneath its approach path and gazing overhead at a passing plane would no doubt know with a reasonable degree of certainty the airspace a plane was using while approaching the threshold of the runway. In sum, we conclude that the County has demonstrated its continuous, uninterrupted use for a fifteen-year period which began during the 1940s when runway 11/29 first opened for use and expired, at the latest, some time before the mid-1960s. E. From Zone To Zone, Guides Through The Boundless Sky Thy Certain Flight: Clear Zones And Avigation Easements By virtue of its acquisition of an avigation easement, the County also obtained the attendant rights of use necessary for its reasonable use and enjoyment. One of the rights incident to its avigation easement is a right to unobstructed clear zones. While avigation and clearance easements may involve distinct property rights, it seems clear that some sort of zone of safety is absolutely essential for the safe use and enjoyment of the County’s avigation easement. Lewis Affidavit at 6. Under Connecticut law, the “owner of an easement has all rights incident or necessary to its proper enjoyment.” Kuras v. Kope, 205 Conn. 332, 533 A.2d 1202, 1206 (1987) (quoting Peterson v. Oxford, 189 Conn. 740, 745, 459 A.2d 100 (1983)); see also American Brass Co. v. Serra, 104 Conn. 139, 150, 132 A. 565 (1926). The court in Kuras recognized that use of an easement frequently involves alterations to the land to make the use possible. See Kuras, 533 A.2d at 1206 (citing Center Drive-In Theatre, Inc. v. Derby, 166 Conn. 460, 352 A.2d 304 (1974)). The Kuras test focuses on whether the desired acts are reasonably necessary to make effective the easement owner’s enjoyment of that easement unless the burden on the servient estate is unreasonably increased. See McCullough, 1992 WL 24332, 1992 Conn. Sup. LEXIS 240. The holding in United States v. Brondum, 272 F.2d 642, does not necessarily conflict with our conclusion. The court in Brondum did not deny the interrelationship between avigation easements and clearance easements. It simply held that the government’s condemnation of property for the express purpose of acquiring one easement does not result, by implication, in its acquisition of the other easement. Id. at 644-45. The message in Brondum is clear: when government exercises its power of eminent domain, it must clearly identify the property rights it seeks to acquire. In this case, the County is prevented from wielding its powers of eminent domain, the easement airspace being located in another state. Despite its somewhat unartful argument and inadequate briefing, it is apparent that the County is expressly seeking both avigation and clearance easements. Most importantly, Connecticut law recognizes that certain incidental rights essential for the use and enjoyment of an easement accrue to the easement’s owner. The presence of a buffer of airspace insures some margin of safety in an emergency. Wind turbulence, or wind shear, is particularly troublesome at low altitudes, in the severest conditions able to displace aircraft fifty feet in a few short seconds. Lewis Affidavit at 6. Clear zones are as unquestionably necessary to the safe operation of aircraft as shoulders are for road safety or channels are for ships approaching harbors. The clear zones that accompany a flight path are not unlike the shoulders that line all roads. Each secures a measure of added safety for those travelling, be it on highways on the ground or in the sky. Courts, assessing the width of highways acquired by prescription, have found that the width of the easement acquired extends beyond simply the beaten track actually used. Prescriptive highway easements are defined to be such widths as are necessary for their safe and convenient use. See, e.g., Grubb v. Teale, 265 Ala. 257, 262,