What are the facts?
The Causbys owned and operated a small chicken farm near a municipally owned airport in Greensboro, North Carolina. During World War II, the United States arranged for intensive military use of the airport, routing large bombers and transport planes directly over the Causbys' property during takeoffs and landings, at all hours of the day and night. On their glide path, aircraft sometimes passed extremely low over the farm—reported at roughly 83 feet above the house, 67 feet above the barn, and about 18 feet above the tallest tree. The noise, vibration, and glare from the aircraft frightened the chickens, causing them to panic, fly into walls, and die (about 150 birds), and substantially reduced egg production. The Causbys ultimately had to abandon their chicken-farming operations. Although the federal government did not own the airport, it authorized and conducted the flights. The Causbys sued the United States under the Tucker Act, alleging that the overflights constituted a taking of their property without just compensation. The Court of Claims awarded compensation, and the case reached the Supreme Court.
What is the legal issue?
Do frequent, low-altitude military overflights directly above private land, which substantially interfere with the landowner's use and enjoyment, constitute a taking of property under the Fifth Amendment requiring just compensation, even though the government does not physically occupy the surface and does not own the airport?
What rule applies?
A landowner owns at least the immediate reaches of the airspace above the land that the owner can occupy or use in connection with the land. While the public has a right of transit in navigable airspace placed in the public domain by Congress, flights that are so low and so frequent as to have a direct and immediate interference with the use and enjoyment of the land effect a taking of an avigation easement requiring just compensation under the Fifth Amendment. Government liability for such a taking does not depend on owning the airport or the surface but on the imposition of a servitude in the airspace.
What did the court hold?
Yes. The government's frequent, low-altitude flights directly over the Causbys' property effected a taking of an easement in the immediate reaches of the airspace, requiring just compensation.
What is the reasoning?
The Court rejected the archaic ad coelum maxim as incompatible with modern aviation but affirmed that property rights include the immediate reaches of airspace necessary to the use and enjoyment of land. On these facts, the aircraft flew at altitudes so low and with such frequency that the intrusion produced a direct, immediate, and substantial interference—destroying the viability of the chicken farm—rather than a mere consequential injury. That degree of interference is tantamount to the government having imposed a continuing servitude (an avigation easement) upon the property. Although Congress may declare the public's right to transit in navigable airspace, at the time the flights here occurred they were below the minimum safe altitudes and thus outside the navigable airspace placed in the public domain. Even if aviation in navigable airspace is privileged, the Constitution still protects the owner's interest in the immediate reaches. The government's role in conducting and authorizing the flights, not ownership of the airport, triggered takings liability because it was the government activity that burdened the property. Consistent with takings doctrine, compensation is measured by the loss in market value of the property interest taken—the easement—rather than by tort-type damages. The Court therefore recognized a compensable taking and remanded for determination of the appropriate scope of the easement and just compensation.
Why is this case significant?
Causby is the cornerstone of aerial takings jurisprudence. It: (1) modernizes property law by limiting ad coelum while preserving landowners' control over the airspace they can practically use; (2) establishes that recurring, low-altitude overflights can be a per se taking of an avigation easement; (3) clarifies that takings liability does not require physical occupation of the surface or government ownership of the facility; and (4) sets the template for later cases, such as Griggs v. Allegheny County, on airport approach paths, and informs contemporary debates over drones and low-altitude operations. For law students, it is essential for understanding how the Takings Clause applies to intangible or non-traditional invasions and how statutory definitions (like "navigable airspace") intersect with constitutional protections.
Did the Supreme Court abolish the ad coelum doctrine in Causby?
No. The Court rejected the doctrine's absolute form as incompatible with aviation but retained a qualified version: landowners own the immediate reaches of airspace above their land—enough to enable ordinary use and enjoyment. Above that, the public has a right of transit in navigable airspace.
Why was this a taking rather than just a nuisance or trespass?
Because the flights were so low and frequent that they imposed a continuing servitude—an avigation easement—on the property, directly and immediately impairing its use and reducing its value. Takings analysis focuses on appropriation or functional occupation (here, of airspace) and requires just compensation, whereas nuisance or trespass would seek damages without recognizing an enduring property interest taken.
Does the government need to own the airport to be liable for a taking from overflights?
No. Causby holds that liability turns on who imposes the servitude on the property. The United States was liable even though the airport was municipally owned, because government-authorized military flights created the low-altitude corridor burdening the Causbys' land.
How low and frequent must flights be to constitute a taking?
There is no bright-line altitude or number. The touchstone is whether the flights are so low and so regular as to cause a direct, immediate, and substantial interference with the land's use and enjoyment (e.g., making ordinary activities impossible, destroying commercial viability, or significantly reducing market value). In Causby, flights as low as roughly 83 feet over structures, occurring day and night, met that standard.
How is just compensation measured in these cases?
Compensation is based on the property interest taken—typically the market value of the avigation easement—often reflected by the diminution in the property's fair market value due to the flight corridor burden. It is not limited to tort-style damages like lost profits or replacement costs, though such evidence may inform valuation.
Did changes to the statutory definition of "navigable airspace" after Causby negate its rule?
No. Later statutes expanded navigable airspace to include approach and departure paths, but Causby's constitutional principle endures: even if airspace is designated navigable, persistent low-level intrusions that directly and substantially interfere with land use can amount to a compensable taking of the immediate reaches.