Boom Supersonic, the American company building what promises to be the world’s fastest airliner, broke the sound barrier for its first time with a test flight in Mojave, California, on Tuesday.

New Concorde' attempts to break sound barrier on first supersonic flight - Boom’s inaugural XB-1 supersonic test flight takes off later today

A prototype of a passenger jet designed to succeed the supersonic Concorde broke the sound barrier for the first time on Tuesday above the Mojave Desert in California. Why it matters: Exceeding Mach 1 speed — 770 miles per hour — is an important milestone in the quest by Boom Supersonic,