Denver-based Boom Technology's XB-1 demonstrator plane hit Mach 1.122 — 750 mph. It's the first independently developed supersonic jet. The company is also working on a supersonic passenger airliner.
Concorde crossed the Atlantic at twice the speed of sound, cutting travel time in half compared to a conventional passenger plane. The groundbreaking jet made its final flight on Nov. 26, 2003.
Boom Supersonic's Overture is designed to travel twice as fast as current airliners and complete transcontinental flights in roughly half the time. Passenger flights are expected to begin in 2029.