It appears drones filling the skies could soon become a way of life. The FAA estimated that during the 2015 holiday shopping season, around 1 million “unmanned aerial vehicles” (UAVs) would be sold. This drone invasion of sorts brings up many legal issues, not the least of which is the rights of drone pilots to fly over private land. Rural property owners and owners of property attractive to thieves would be particularly interested – does a landowner have any rights to the airspace above his property? This article looks at that question under Colorado law.
Under the ancient common law “ad coelum” doctrine, a landowner owned everything below and above his property. See, e.g., United States v. Causby, 328 U.S. 256, 261 (1946) (citing English jurists Blackstone and Coke). Colorado has adopted the “ad coelum” doctrine via a statute, with a major exception for aircraft:
“The ownership of space above the lands and waters of this state is declared to be vested in the several owners of the surface beneath, subject to the right of flight of aircraft. ” C.R.S. § 41-1-107.
Two Colorado cases have construed this statute when analyzing whether frequent aircraft flyovers of private property amounted to a “taking” of private property for public use, that is, a taking of an “avigation” easement. See Claassen v. City & Cty. of Denver, 30 P.3d 710, 713 (Colo. App. 2000); Thompson v. City and County of Denver, 958 P.2d 525, 527 (Colo. App. 1998). In both decisions the court explained that “navigable” airspace is in the public domain, and so the plaintiff landowners had no property rights in such airspace. Claassen, 30 P.3d at 713; Thompson, 958 P.2d at 527. Federal regulations define “navigable” by, in effect, limiting aircraft’s operational altitude to 1,000 feet in “congested” areas and 500 feet in other areas. 14 C.F.R. § 91.119. In both Colorado cases, the court determined there was not a taking because the aircraft stayed in the “navigable” space – it did not matter how frequently or loudly aircraft flew over the plaintiffs’ property. Thus, in Colorado, drones aircraft flying at altitudes of at least 500 or 1,000 feet (as the case may be) would not trespass on the rights of property owners.
However, in practice drones will not be flying at those altitudes. In fact, the FAA is poised to require that drones generally stay below navigable airspace so they don’t pose a threat to manned aircraft. So, what does Colorado law say about the low-altitude airspace? After mentioning Colorado’s ad coelum statute, the court in Thompson suggested that the statute was not to be taken literally. The court said “a landowner’s property interest in the land extends to the airspace directly over the property to the extent that the airspace can be used to benefit the underlying land.” Thompson, 958 P.2d at 527. The court cited United States v. Causby, wherein the United States Supreme Court made similar observations. See 328 U.S. 256, 264 (1946) (citations omitted). Thus, the Thompson and Causby cases take a very narrow view of a property owner’s airspace rights.
However, when interpreting the Thompson case, the court in the later Claassen case suggests that property owners’ rights extend to the “navigability” threshold: “[W]e conclude that, absent a physical invasion into the airspace above plaintiffs’ property that is below the navigable airspace, there can be no physical taking within the meaning of [the Colorado constitution].” This appears to be the same view expressed in the Colorado case of People v. Emmert. In this case, defendants were charged with criminal trespass after they floated and fished through private property on a non-navigable stream. 597 P.2d 1025, 1026 (Colo. 1979). The court opined that the ad coelum doctrine was strongly entrenched in Colorado via earlier case law and statute. The court then explained that the streambed owner had “the exclusive right of control of everything above the stream bed, subject only to constitutional and statutory limitations, restrictions and regulations.” Id. at 140-41.
Accordingly, someone flying a drone over another’s property without permission below the navigability threshold likely commits a trespass under Colorado law. However, the property owner should not act on a visceral impulse to shoot down a trespassing drone. Under federal criminal law, shooting down a drone is probably a criminal act. The applicable statute criminalizes the destruction of “any civil aircraft used, operated, or employed in interstate, overseas, or foreign air commerce.” 18 U.S.C. § 32(a)(1). “Aircraft” is defined broadly and probably includes drones. Second, a mere trespass, without danger to your person or property, would not likely justify destruction of the trespassing property.
 The FAA’s current policy on “model airplanes” suggests a limit of 400 feet. See Advisory Circular No. 91-57A, Federal Aviation Administration, 1/11/2016, available at http://www.faa.gov/documentLibrary/media/Notice/Notice_UAS_7210.891.pdf. The FAA is also working on comprehensive regulations for “small unmanned aircraft systems” and currently proposes an altitude limit of 500 feet. See https://www.faa.gov/uas/nprm/.
 The term “aircraft” means a civil, military, or public contrivance invented, used, or designed to navigate, fly, or travel in the air. 18 U.S.C. § 31(a)(1).
Posted by Jeffrey Cullers