Fifty years ago, the federal government banned all civilian supersonic flights over land. The rule prohibits non-military aircraft from flying faster than sound so their resulting sonic booms won't startle the public below or concern them about potential property damage.

Supersonic flight over land is currently banned in most countries primarily because of the sonic boom—a thunderous noise created when an aircraft breaks the sound barrier (Mach 1). When the Concorde operated, the shockwaves it generated were powerful enough to rattle windows, distress livestock, and cause significant noise pollution for communities beneath its flight path. Consequently, the FAA in the US and similar bodies globally restricted supersonic speeds to over-ocean routes only. Additionally, early supersonic engines were notoriously inefficient and loud during takeoff and landing, failing to meet modern 2026 environmental and noise-abatement standards. However, the "ban" is beginning to evolve; in 2026, NASA’s X-59 Quesst aircraft is undergoing testing to demonstrate "quiet" supersonic technology, which replaces the "boom" with a "thump" about as loud as a car door closing. If this technology is proven successful and safe, regulatory bodies may consider lifting the overland ban for a new generation of sustainable supersonic commercial jets, but until then, the environmental impact and "boom" noise remain the legal and social barriers to faster-than-sound travel.