The Air Commerce Act of 1926 declared the navigable airspace of the United States to be free for use.
Notes on verification
Confirmed by codified U.S. Code language, federal appellate precedent (Cheyenne Airport Board v. Rogers), and U.S. Supreme Court decision (United States v. Causby, 1946), plus scholarly legal commentary.
Sources
- How Much of the Sky Overhead Do You Own? (smithsonianmag.com)
- https://supreme.justia.com/cases/federal/us/328/256 (supreme.justia.com)
- https://tile.loc.gov/storage-services/service/ll/uscode/uscode1925-00304/uscode1925-003049006/uscode1925-003049006.pdf (tile.loc.gov)
- https://www.courtlistener.com/opinion/1268737/cheyenne-airport-board-v-rogers/ (courtlistener.com)
- https://www.cambridge.org/core/journals/cambridge-law-journal/article/abs/property-in-thin-air/8577254C1FABAA2C1945FA55C82A8EE6 (cambridge.org)