Currently, all civil aircraft flights are prohibited from operating above Mach one speeds over land in the United States. Aircraft companies seeking to advance the testing of civil supersonic aircraft require a special flight authorization (SFA) under 14 CFR § 91. 818 (“Special flight authorization to exceed Mach 1”) to flight test the next generation of supersonic (speed) capable vehicles. Issuance of SFAs is considered a major federal action under the National Environmental Policy Act (NEPA). As a result, the FAA must complete an environmental review of SFA issuance in compliance with NEPA and other environmental laws and requirements (see FAA Order 1050.1G: FAA National Environmental Policy Act Implementing Procedures). 

The FAA publishes notice of SFA applications and the availability of accompanying environmental review documents in the Federal Register. The following applications have been received by the FAA and are undergoing review:  

• SFA for Boom Technology XB-1 Supersonic Test Flights
  • Granted Special Flight Authorization (SFA) to Exceed Mach 1 for Boom Technology (effective April 7, 2024)
  • Final Environmental Assessment for Boom Technology XB-1 Supersonic Test Flights from the Mojave Air and Space Port, Mojave CA
  • Boom EA Final Finding of No Significant Impact for Boom Technology XB-1 Supersonic Test Flights
• SFA for Hermeus Testing of the Supersonic Quarterhorse Mark 2.1 Unmanned Aircraft System
  • Notice of decision to grant an authorization to exceed Mach 1. 
  • Granted Special Fight Authorization (SFA) to Exceed Mach 1 (effective April 9, 2026)
  • Reliance on and Adoption of Environmental Impact Statement and Record of Decision for the Hermeus SFA to Conduct Testing of the Supersonic (Greater than Mach 1.0) Quarterhorse Mark 2.1 Unmanned Aircraft System Over Land at White Sands Missile Range, New Mexico.

For further information, please email 9-APL-AEE-NEPA-Comments@faa.gov.