Imagine that Amazon’s Jeff Bezos releases drones, a.k.a. unmanned aerial systems (“UAS”), in your neighborhood which fly over your property to deliver goods to your neighbors. Do you have the right to stop Bezos’ UAS from flying over your house?
Landowners may assert their rights to airspace using a claim based in trespass or nuisance. This article focuses on a trespass theory. Under Wisconsin law, a “trespasser” is one who enters or remains upon land in the possession of another without consent. Grygiel v. Monches Fish & Game Club, Inc., 2010 WI 93, ¶40-41, 328 Wis. 2d 436, 461, 787 N.W.2d 6, 18; Wendt v. Manegold Stone Co., 240 Wis. 638, 639, 4 N.W.2d 134 (1942). To state a claim for trespass, the claimant must show both that (i) he has a right of possession or ownership of the real property at issue and that (ii) the trespasser has intentionally entered that real property.
As to the second element, it is important to understand that the legal “wrong” of trespass is the interference with the possessor’s interest in excluding others from his land. The landowner is harmed by the mere fact of unpermitted entry regardless of whether the trespasser actually damages any other legally protected interest of the landowner.
The first element, the extent of a landowner’s rights to the airspace above his land, can be a fairly tricky issue. The general common law rule in Wisconsin is that a trespass may be committed on, beneath, or above the surface of the earth. Restatement (Second) of Torts § 159 (1965); Steiger v. Nowakowski, 67 Wis. 2d 355, 359, 227 N.W.2d 104, 106 (1975). Furthermore, as defined by Wis. Stat. § 844.01(2), a physical injury to real property includes unprivileged intrusions to the “surface, subsurface or suprasurface.” A trespass may therefore occur in airspace.
For example, the following acts and conditions have been found to constitute a trespass: telephone wire strung across another’s land at a height varying from 20 to 30 feet, constructing a board to extend out from a building and over the property line, constructing eaves so as to overhang a neighbor’s property, thrusting one’s arm into the space over a neighbor’s land, shooting over another’s land, and tree branches overhanging the lot line. See Swetland v. Curtiss Airports Corp., 41 F.2d 929, 935-36 (N.D. Ohio 1930).
It is therefore easy to see why an Amazon delivery drone would trespass by hovering 3 inches in the air across your yard. Higher altitudes pose a more difficult question. As discussed, a landowner cannot prevail on a trespass claim unless he owns or possesses a real property interest. How can you own or possess the sky?
Prior to the modern invention of airplanes, satellites, and skyscrapers, the common law rule was that a landowner’s rights extend infinitely to the airspace above and the ground below the land. Early Wisconsin cases were generally in accord with the common law rule. See generally Huber v. Stark, 124 Wis. 359, 102 N.W. 12 (1905).
The introduction of the airplane forced a rethinking of the common law. Twenty-two states, including Wisconsin, adopted the Uniform Aeronautics Act (the “WUAA”). Wis. Stat. § 114.01 et seq. The WUAA vests ownership of airspace to the landowner subject to a public right of flight. Wis. Stat. § 114.03. Flight is lawful “unless at such a low altitude as to interfere with the then existing use to which the land or water, or the space over the land or water, is put by the owner, or unless so conducted as to be imminently dangerous or damaging to persons or property lawfully on the land or water beneath.” Wis. Stat. § 114.04.
The plain language of the WUAA teaches that a UAS may fly above your property, however it may not do so in a dangerous manner nor at an altitude which is so low as to interfere with the landowner’s existing use of the land or airspace.
How low is too low for a UAS? There is no exact fixed height set in section 114.04, Wis. Stats. As stated by Maitland v. Twin City Aviation Corp., “[t]he height below which the surface owner may reasonably expect to occupy the airspace for himself is to be determined upon the particular facts of each case.” 254 Wis. 541, 544, 37 N.W.2d 74, 75 (1949). Thus, because land use varies by landowner (such as a skyscraper versus a farm), it stands to reason that the altitude at which UAS flight interferes with the landowner’s use varies as well.
The Supreme Court considered the extent of a landowner’s rights to airspace in United States v. Causby. 328 U.S. 256, 261, 66 S. Ct. 1062, 1065, 90 L. Ed. 1206 (1946). Causby owned a chicken farm within 2,300 feet from an airfield used by the United States Army and Navy. Military aircraft passed over Causby’s property at elevations as low as 83 feet during takeoffs and landings. Causby alleged that the noise frightened and killed his chickens, thereby ruining his farm’s production. Causby sued the U.S. government under the Fifth Amendment, alleging that the frequent and regular low altitude flights over his farm constituted a taking of his property without just compensation.
Because the government cannot “take” private property from a person unless that person actually owns a property interest, a key component of Causby was determining the extent of a landowner’s rights to the airspace above his land. Although the Supreme Court did not set out a test for determining the extent of a landowner’s airspace rights, the court recognized that a property owner owns at least as much of the space above the ground as he can occupy or use in connection with the land. For such airspace “enveloping” the property, a physical invasion may constitute a taking where the government’s use (i.e., airplane flight) is so low and so frequent as to be a direct and immediate interference with the use and enjoyment of the land. The court held that the government’s (i) constant and (ii) low altitude flights of large military aircraft met this standard, having the effect of interfering with Causby’s use of his land and enveloping airspace. As a result, the court found that the government imposed an avigation easement on Causby’s real property and remanded for additional fact finding to determine the proper measure of compensation.
Importantly, the court also found that at some point airspace becomes a public highway for flight. The Supreme Court rejected the common law rule, stating that “[c]ommon sense revolts at the idea” of subjecting every transcontinental flight to countless trespass lawsuits. For guidance the court looked to the Air Commerce Act of 1926 and related regulations enacted pursuant to the Civil Aeronautics Act of 1938, which state that the United States has “complete and exclusive national sovereignty” in navigable airspace. Navigable airspace was defined by a proscribed minimum altitude of safe flight (which may be generally summarized as being 500 feet above the surface, or 1000 feet above the highest obstacle in congested areas, such as a city). See 14 C.F.R. § 91.119. Finding that “navigable airspace” is a public highway to which only the public has a claim, the court set navigable airspace as a public zone above a landowner’s claim to the airspace above his land.
The Causby court thus conceptually divided the sky into two separate domains: an upper altitude subject to the public’s right of flight and a lower altitude which could be potentially owned by the landowner. The lesson is that a UAS likely would not be trespassing in an uncongested area at an altitude of 500 feet or higher. Conversely, a UAS will trespass at or very near the surface and additionally at higher altitudes where the landowner can show that the UAS actually interferes with the landowner’s use of real property based upon such factors as the altitude, frequency, and impact of the UAS flights.
Unfortunately, the case law after Causby has struggled to determine the exact extent of the public and private domains. Worse still, UAS does not fit neatly into this case law. UAS can be much smaller, quieter, and have a smaller impact on the use of the land than the aircraft considered in Causby. Furthermore, as UAS technology develops and the Federal Aviation Authority promulgates new regulations for UAS flight, UAS may be able to operate safely at altitudes previously unconsidered by the courts. As a result, it cannot be stated with certainty exactly which altitudes a UAS may fly without trespassing on a landowner’s property.
In conclusion, the closer a UAS is to the ground, the more likely it is to trespass on your property. The WUAA and case law set out two guide posts for measuring the extent of the rights of the landowner and the public to airspace: (i) the impact on the landowner’s then existing use of the land and enveloping airspace; and (ii) the minimum safe flight altitude (which for airplanes is 500 feet in uncongested areas or 1000 feet in a congested area, such as a city). FAA regulations may clarify the second benchmark for UAS in the future, but the first benchmark likely will remain a case-by-case determination for the courts to determine.
If you have any questions about how the information in this article may affect you or your business, please contact your Stroud attorney.
DISCLAIMER: The information in this article is provided for general informational purposes only, is not necessarily updated to account for changes in the law, and should not be considered tax or legal advice. This article is not intended to create, nor does the receipt of it constitute, an attorney-client relationship. You should consult with your own legal and/or financial advisors for legal and tax advice tailored to your specific circumstances.