Test Flights

NASA X-59 Quesst Breaks Sound Barrier After Nearly Seven Months of Careful Test Flights

The NASA X-59 Quesst aircraft, built by Lockheed Martin Skunk Works, took roughly seven months from its first flight on October 28, 2025, to safely cross the sound barrier for the first time on June 5, 2026. Rather than immediately flying at full speed, experimental aircraft must undergo a careful process called envelope expansion. Even though the X-59 is intended to pioneer quiet supersonic flight for commercial airliners, engineers must slowly push the aircraft's limits to ensure it remains safe and controllable.