Who Owns the Sky? The Case for a Statutory Altitude Floor

Darcy Yin

Edited by Jordan Perlman, Emily Mandel, Mac Kang, and Sahith Mocharla

In 2015, a Kentucky man shot a drone out of the sky some twenty feet above his property. He was arrested and charged with criminal mischief, but the charges were dropped after a state court concluded the drone had indeed been invading his privacy [1]. When the drone's owner brought the matter to federal court seeking a ruling on whether low-altitude drone flight constitutes public airspace or private property, the court dismissed the case on jurisdictional grounds, declining to treat the matter as a federal issue [2]. Fundamentally, though, that dismissal was misguided. The question of who controls the airspace above private property ought to be a central piece of federal law, and the absence of such a policy is why the legal framework governing low-altitude airspace remains broken over a decade later. In the context of the existing preemption doctrine, the Federal Aviation Administration’s (FAA) federal airspace authority is a stronger legal framework than the states’ piecemeal demarcations, and Congress must create a clear altitude floor to make that authority enforceable at low altitudes.

Understanding why requires tracing how the law arrived at its current impasse. Under common law, land ownership extended indefinitely upward under the ad coelum doctrine. This principle states that a landowner owns everything above and below their land, from the heavens down to the center of the earth. It functioned adequately before the advent of flight, as nothing meaningfully occupied that space. 

However, the rise of commercial aviation made such an arrangement untenable. In United States v. Causby (1946), the Supreme Court confronted this problem directly [3]. Flying as low as 83 feet over a North Carolina chicken farm, Army bombers created extreme noise and glare that killed over 150 chickens and made the property effectively uninhabitable [4]. Causby, the owner of the farm, invoked the ad coelum doctrine to argue that the government had confiscated his property without just compensation. The Court recognized that very low flights can directly interfere with a landowner’s use and enjoyment of land, constituting a violation of the Taking Clause of the Fifth Amendment [5]. At the same time, the Court acknowledged that if landowners retained an infinite upward ownership from the ground, every transcontinental flight would be fair grounds for a trespass suit, and neither government nor commercial aviation would function. The old doctrine, as Justice William Douglas wrote, “has no place in the modern world” [6]. Airspace above navigable altitude thus became public domain. To balance these competing concerns, the Court established the “immediate reaches” standard, under which landowners retain rights to the airspace they can genuinely occupy and use, while airspace above that belongs to the public [7]. The Court, however, declined to define the bounds of “immediate reaches,” and this uncertainty is where every modern dispute begins.

Congress created the FAA in 1958 and vested it with exclusive national authority over all navigable airspace of the United States, hoping to create a uniform federal code that all states would abide by [8]. The FAA has consistently read this mandate to extend from the ground up. When drones entered the commercial market, the FAA set a maximum operating altitude of 400 feet above ground level with no corresponding minimum, pushing drone operations squarely into the low-altitude zone that Causby had left legally undefined [9]. Forty-four states responded by enacting their own drone laws, producing precisely the fragmented state-by-state regulatory scene the FAA’s mandate was designed to prevent [10].  Reconciling the FAA’s authority to govern airspace with landowner rights brings into play two Supreme Court decisions that seemingly pull in opposite directions. Read together, though, these two cases do not actually conflict so much as they govern different domains. Causby sets the precedent that landowners do not own the airspace above the “immediate reaches” of their property, treating higher airspace as a “public highway” [11]. In contrast, Cedar Point Nursery v. Hassid (2021) holds that the right to exclude is a fundamental property right and that a California regulation granting union organizers access to private farmland constituted a per se physical taking [12]. Cedar Point's right-to-exclude framework is inherently unworkable if applied to all airspace from the ground upward, as it would effectively resurrect the ad coelum doctrine Causby rejected and give every landowner a veto over any overflight. But Cedar Point's logic remains sound when applied, as it was, to the physical occupation of surface property by human beings, which is a categorically different encroachment than transient aerial passage at operational altitude [13]. Landowners would retain meaningful exclusion rights in the airspace they can genuinely occupy and use, consistent with Cedar Point, while the airspace above that belongs to the public under Causby's “direct and immediate interference” standard [14].

Courts began confronting the right of states to enact their own regulations in cases such as Singer v. City of Newton (2017), in which a federal court in Massachusetts struck down a city ordinance banning drone operations below 400 feet over private property [15]. The court found the ordinance to be conflict-preempted, concluding that it effectively constituted a wholesale ban on drone use within city limits and directly frustrated Congress's goal to integrate drones into the national airspace [16]. The court, however, stopped short of declaring that the FAA occupies the entire regulatory field, leaving some room open for state interpretation [17].

Extending the landowner exclusion framework beyond that zone also runs into a serious problem. Negotiating easements with every property owner beneath any planned flight path would give each landowner the independent power to block any flight over their land. This would make it impossible to maintain a federal airspace, let alone any coordinated national drone grid. An analysis of Causby's consequences for drone law by attorneys from Wiley Rein LLP makes this point plainly, warning that state-imposed per se trespass regimes below any fixed altitude would produce a “warren of restricted airspace” that is irreconcilable with the FAA’s congressional mandate [18]. Leaving airspace questions to the states would also directly violate the Commerce Clause, as drone activity, such as delivery, surveying, and emergency response, is inherently interstate commerce [19]. 

What is needed as the next logical step, then, is a statutory altitude floor that removes states’ rights to independently define where public domain ends. The 2024 FAA Reauthorization Act addressed drone reform but focused very narrowly on beyond-visual-line-of-sight (BVLOS) safety standards, leaving the low-altitude property rights conflict completely out of the document [20]. As Vanderbilt Policy Accelerator’s analysis of drone delivery regulation writes, partial reform of this kind entrenches existing harms rather than correcting them, because only legislating BVLOS safety approvals without changing the foundational structural problems essentially green-lights the industry to scale around the gaps rather than forcing Congress to close them [21]. Congress must define a clear altitude threshold, below which state trespass laws apply, and above which the airspace is unquestionably federal. This gives landowners defined constitutional protections for the airspace beneath that line and resolves the preemption question that Singer left open [22]. 

Every day that Congress leaves America’s airspace undefined, forty-four states continue defining it for themselves, and cases like Kentucky Drone Slayer never find a resolution. Instituting a statutory altitude floor is how that ends.

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[1] Boggs v. Merideth, No. 3:16-CV-00006-TBR, 2017 U.S. Dist. LEXIS 40302 (W.D. Ky. 2017)

[2] see [1]

[3] U.S. v. Causby, 328 U.S. 256 (1946)

[4] see [3]

[5] see [3]

[6] see [3]

[7] see [3]

[8] 49 U.S.C. § 40103

[9] Fed. Aviation Admin., State and Local Regulation of Unmanned Aircraft Systems (UAS) Fact Sheet (2023), https://www.faa.gov/sites/faa.gov/files/uas/public_safety_gov/public_safety_toolkit/FAA%20UAS%20Fact%20Sheet.pdf

[10] see [9]

[11] see [3]

[12] Cedar Point Nursery v. Hassid, 594 U.S. 139 (2021)

[13] see [12]

[14] see [3]

[15] Singer v. City of Newton, 284 F. Supp. 3d 125 (D. Mass. 2017)

[16] see [15]

[17] see [15]

[18] Joshua S. Turner & Sara M. Baxenberg, Causby and effect: How the Uniform Law Commission's misplaced reliance on a 1946 Supreme Court case threatens the drone industry, WESTLAW JOURNAL AVIATION (Oct. 17, 2018), https://www.wiley.law/assets/htmldocuments/Causby_And_Effect.pdf

[19] U.S. Const. art. I, § 8, cl. 3

[20] Ramsay Eyre, Regulating Drone Delivery, VANDERBILT POLICY ACCELERATOR (Nov. 1, 2024), https://cdn.vanderbilt.edu/vu-URL/wp-content/uploads/sites/412/2024/10/31150600/VPA_Regulating_Drone_Delivery.pdf

[21] see [20]

[22] see [15]