Today a civil test airliner, Boom Technology’s XB-1, broke the sound barrier for the first time in two decades.

"The second half of our test campaign is all about expanding XB-1's envelope incrementally in altitude, air speed, and Mach number until we inevitably make that sonic boom," Nick Sheryka ...

Boom Supersonic ’s XB-1 aircraft climbed over 35,000 feet on Tuesday before accelerating to Mach 1.1 speed and breaking the ...