FAA Supersonic Flight Rule Would End 50-Year Overland Speed Ban

The Federal Aviation Administration has issued a Notice of Proposed Rulemaking (NPRM) to establish a new FAA supersonic flight rule that would repeal the blanket prohibition on civil supersonic flight over U.S. land in place since 1973. Rather than an outright speed limit, the proposed regulation sets an interim noise-based certification standard: aircraft may exceed Mach 1 provided their sonic boom overpressure at the surface does not exceed 0.11 pounds per square foot (psf). Operators may use measurement, modeling, or other FAA-approved methods to demonstrate compliance, giving manufacturers flexibility in how they meet the threshold.

The performance-based approach is designed to enable low supersonic cruise speeds — potentially up to Mach 1.3 — by exploiting "Mach cutoff" atmospheric refraction, which bends shockwaves upward and away from the ground before they reach populated areas. The technical basis for the 0.11 psf limit draws on flight data from Boom Supersonic's XB-1 demonstrator and NASA's X-59 quiet supersonic research aircraft, both programs aimed at reducing the traditional sonic boom to a barely perceptible thump. The NPRM follows a June 6, 2025, presidential executive order titled "Leading the World in Supersonic Flight," which directed the FAA to remove regulatory barriers for next-generation supersonic aviation.

Regulatory Timeline

The current NPRM addresses en-route noise only; the FAA plans to issue a separate proposal covering supersonic landing and takeoff (LTO) noise in December. An integrated final rule is targeted for mid-2027. Once in force, the FAA supersonic noise standard would eliminate the need for case-by-case special flight authorizations, paving the way for routine domestic and transcontinental supersonic corridors — and accelerating the commercial ambitions of manufacturers developing civilian supersonic transport concepts.