The Civil Aeronautics Authority, a predecessor of the FAA, claimed all airspace above 500 feet as public domain.
Notes on verification
Confirmed by primary Supreme Court text (US v. Causby, 328 U.S. 256) and independently corroborated by FAA history page, Cornell Law, Findlaw, and secondary legal commentary. Accurately paraphrases the daytime minimum safe altitude of 500 feet as the threshold for public domain airspace. [cascade flags: wikipedia_dropped_other_sources_exist | tier=silver indep_score=0.95 clusters=3 claim_tier=notable | framework convergence=single on The Supreme Court's opinion in United States v. Causby, which quotes the statutory definition of navigable airspace under the Civil Aeronautics Act (upstreams: United States v. Causby, 328 U.S. 256 (1946) opinion, Air Commerce Act of 1926, Civil Aeronautics Act of 1938) — publishers independent, evidence may not be | kind=empirical eligibility=high (extractor: empirical/medium)]
Sources
- How Much of the Sky Overhead Do You Own? (seed:law_and_crime)
- https://caselaw.findlaw.com/court/us-supreme-court/328/256.html (corroboration)
- https://law.cornell.edu/supremecourt/text/328/256 (corroboration)
- https://www.faa.gov/about/history/brief_history (corroboration)