Plaintiffs (including Hinman) owned and occupied land and a dwelling over which defendant Pacific Air Transport, a commercial air carrier, regularly routed its aircraft. The complaint alleged that defendant's planes flew directly over the property on repeated occasions, sometimes at relatively low altitudes, generating substantial noise, vibration, and disturbance (including bright lights at night), thereby interfering with plaintiffs' comfort and ordinary use of the home and premises. Plaintiffs sued, characterizing the overflights as a continuing trespass and seeking damages and injunctive relief. The carrier defended on the theory that flight through airspace above the land was not a trespass because landowners did not own a vertical column of air to the sky, and that lawful flight consistent with federal aviation regulation was privileged. The district court treated the pleadings as insufficient to state a trespass claim under the asserted airspace ownership theory, and the matter came to the Ninth Circuit to determine the nature and scope of the landowner's rights in the air and the proper theory of liability, if any, for overflights.
Does a landowner own the airspace above the surface to such an extent that aircraft flying overhead commit a trespass, or, instead, are overflights actionable only if they amount to a nuisance by substantially interfering with the owner's use and enjoyment of the land?
A landowner does not own an unlimited column of air above the surface. The owner's property interest extends only to so much of the airspace as the owner can occupy or use in connection with the land. Accordingly, mere overflight at heights that do not interfere with the ordinary use and enjoyment of the land is not a trespass; however, flights that are so low, frequent, or disruptive as to cause substantial interference may constitute a nuisance and support damages or equitable relief.
The court rejected the literal ad coelum doctrine and held that overflights at reasonable altitudes are not trespasses. Nevertheless, the complaint stated a cognizable claim sounding in nuisance to the extent the alleged low and disruptive flights substantially interfered with plaintiffs' use and enjoyment of their land. The case could proceed on a nuisance theory rather than trespass.
The Ninth Circuit reasoned that the historical maxim cujus est solum, ejus est usque ad coelum—absolute ownership to the periphery of the universe—was an outmoded fiction when confronted with modern aviation. Property concepts serve practical ends: the law protects those incidents of ownership that facilitate beneficial use of land. Because landowners neither occupy nor can feasibly control all air at indefinite heights, recognizing absolute dominion over the sky would unduly burden a socially valuable mode of transportation and create insuperable liability for every routine overflight. At the same time, the court emphasized that aviation is not categorically privileged to injure landowners. Trespass protects the interest in exclusive possession, which does not extend to all heights above the surface; thus, mere passage of aircraft through higher airspace does not invade a possessory interest and cannot be a trespass. By contrast, nuisance protects the interest in use and enjoyment. Low, frequent, or otherwise disruptive flights that generate noise, vibration, light, or dust can substantially interfere with residential use, and when they do, the landowner may recover in nuisance even if the aircraft traverse airspace generally open to public flight. Federal regulation of aviation (e.g., definitions of navigable airspace and rules of the air) informs whether a flight is reasonable but does not immunize conduct that causes substantial, localized harm to land use. Balancing these considerations, the court concluded that a bright-line rule of trespass to an infinite vertical column was unwarranted. Instead, it adopted a functional rule: the landowner owns and can protect as much airspace as is reasonably necessary to the ordinary uses of the land, and aviation beyond that sphere is generally lawful unless it crosses the line into nuisance by materially impairing those uses.
Hinman is a cornerstone of American airspace law. It (1) rejects the literal ad coelum doctrine, (2) clarifies that overflight liability typically sounds in nuisance, not trespass, and (3) supplies the functional "use-and-occupancy" approach to airspace that later evolved into the "immediate reaches" concept embraced by the Supreme Court in United States v. Causby. The case is frequently taught for its method of adapting common-law property principles to technological change and for its enduring influence on contemporary issues, including airport siting, noise litigation, and drone operations.
Hinman v. Pacific Air Transport modernized property law's treatment of airspace by rejecting absolute dominion in favor of a use-oriented conception. It preserves landowners' essential interests by protecting airspace they actually occupy or reasonably need while legitimizing aviation's use of higher airspace as non-trespassory.