FAA Proposes Rules to Legalize Supersonic Flight Over US

The Federal Aviation Administration (FAA) has issued a notice of proposed rulemaking that would lift the 1973 prohibition on civil supersonic flight over the continental United States. This pivotal shift, announced by US Transportation Secretary Sean P. Duffy, moves toward a noise-based certification standard. Under the new framework, advanced aircraft will be legally permitted to fly faster than Mach 1, provided their sonic signature does not exceed a ground-level overpressure of 0.11 pounds per square foot. This updated policy aims to foster American innovation and safely reintroduce high-speed commercial travel domestically.

Aerospace engineering advancements have made it possible to mitigate sonic booms. Recent technological milestones demonstrate that sonic booms can be transformed into a faint atmospheric thump rather than a disruptive sound. Boom Supersonic successfully flew its XB-1 demonstrator aircraft over the Mojave Desert in early 2025, shattering the sound barrier and validating its Boomless Cruise technology. This technology utilizes the physics concept of Mach cutoff, allowing the sonic boom to refract into the atmosphere before reaching the ground by flying at specific altitudes and speeds.

NASA also verified similar noise-reduction theories with its X-59 experimental aircraft, which achieved supersonic flight in June 2026. These technological validations pave the way for next-generation commercial airliners capable of significantly reducing travel times across the country. Private aerospace firms are actively developing new supersonic aircraft to leverage this modernized regulatory landscape. Boom Supersonic, for instance, is developing the Overture commercial jetliner, with major carriers like United Airlines expressing interest in its fleet.