Boom Supersonic independently designed and built the XB-1, the first civil supersonic jet in America. The XB-1's first supersonic flight last month was a

The last time anyone other than a fighter pilot went supersonic was 20 years ago. Today, you can only visit a Concorde in a handful of museums. It's a relic, left behind by an industry that invested in efficiency rather than speed.

The scaled-down prototype, nicknamed the "Baby Boom", broke the sound barrier for the first time during a test flight over the Mojave Desert in California in late January. The small jet, officially called XB-1, reached an altitude of 35,000 feet before accelerating to Mach 1.1 (844mph) – "10% faster than the speed of sound", said Sky News.