The Federal Aviation Administration has proposed a change that could mark one of the most significant regulatory shifts in civil aviation in recent decades. On June 30, 2026, the FAA published a proposed rule that would lift the long-standing general ban on civil supersonic flight over land in the United States, introduced in 1973 due to concerns over sonic booms. Instead of the current speed-based ban, the new approach would be based on noise — specifically on whether a sonic boom reaches the ground and how intense it is.

Under the FAA proposal, civil aircraft would be allowed to fly faster than Mach 1 over U.S. territory if the sonic boom overpressure at the surface does not exceed 0.11 pounds per square foot. Operators would have to demonstrate, through measurement, modelling or another FAA-approved method, that the flight does not generate an unacceptable sonic boom on the ground and that an operational control method is in place to prevent such an effect during actual operations. In its proposal, the FAA states that the current section 91.817, which effectively prohibits civil supersonic flight over the United States, would be revised into a rule allowing such operations under clearly defined conditions.

The key difference compared with the current regime lies in the concept of so-called “Mach cut-off” flight. This is a flight regime in which a combination of speed, altitude and atmospheric conditions causes shock waves to refract back into the atmosphere instead of reaching the ground as a conventional sonic boom. In its explanation, the FAA also refers to NASA research, according to which only very weak, low-frequency sounds may be heard on the ground in such conditions, described as a “rumble” comparable to background urban noise.

For now, the proposal applies only to en-route supersonic flight. The FAA has also announced that it plans to propose separate rules later this year for noise standards during take-off and landing of supersonic aircraft. This should provide manufacturers and operators with a clearer regulatory framework for developing a new generation of supersonic aircraft, while also seeking to avoid a repeat of the problems that limited Concorde’s operations over land. In its official announcement, the FAA said the goal is to enable civil supersonic flights over the continental United States without a conventional sonic boom, arguing that advances in aerodynamics, materials, noise control and new operational concepts have changed the situation compared with the 1970s.

The 1973 ban was one of the key reasons why Concorde, although technologically impressive, was never able to realise its full commercial potential on overland routes. Regular commercial supersonic flights ended in 2003 with the retirement of Concorde, and since then the industry has made several attempts to return to the concept, but without a successfully certified new-generation passenger aircraft.

That is why the FAA proposal comes at a time when interest in supersonic flight is once again accelerating. U.S.-based Boom Supersonic is developing the Overture passenger aircraft, while its XB-1 demonstrator broke the sound barrier over the Mojave Desert in January 2025, reaching Mach 1.1. Reuters reported at the time that the XB-1 became the first privately funded aircraft to break the sound barrier, while Boom says it has orders and pre-orders for Overture from United Airlines, American Airlines and Japan Airlines.

Boom has also been highlighting the possibility of so-called “boomless cruise” operations, meaning supersonic cruise without a sonic boom being heard on the ground. Such a concept would not necessarily mean maximum speeds comparable to classic oceanic supersonic flight, but it could allow faster flights on routes within the United States, such as between the East and West Coasts, reducing travel times without fully undermining acceptability for communities beneath the flight path.

Additional regulatory and technological context is provided by NASA’s X-59 Quesst programme. On June 12, 2026, NASA announced that the experimental X-59 had reached Mach 1.4 at an altitude of 55,000 feet, conditions in which the aircraft is expected to conduct future overflights above U.S. communities to collect data on public response to a quieter “sonic thump”. These data should help regulators define future standards for acceptable noise levels from supersonic flights over land.

However, the FAA proposal does not mean that regular supersonic passenger flights over the United States are about to return immediately. This is still a proposed rule, and the FAA will accept public comments for 45 days. In addition to the final regulatory decision, manufacturers still need to solve a series of technical, economic and environmental challenges: engine development, fuel consumption, emissions, airport-area noise, operating costs and, ultimately, certification of an entirely new aircraft type.

Still, the change in regulatory logic is highly significant. Instead of banning supersonic speed as such, the United States is now considering a model in which the actual impact of the flight on the ground is what matters. If this approach passes public consultation and is adopted as a final rule, civil supersonic aviation could, for the first time in more than half a century, gain a realistic regulatory path back over U.S. land.