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.

The Colorado-based company is aiming to build a Concorde-like supersonic aircraft—but has hurdles to clear before realizing that goal.

Boom Supersonic passed a major milestone Tuesday on its path to reintroduce supersonic commercial flights. After years of testing and refinement, a pilot flying the aerospace company’s XB-1 scale prototype finally broke the sound barrier during a livestream event—not once, not twice, but three times.