“The XB-1 program provides the foundation for the design and development of Overture, Boom’s supersonic airliner, while establishing a safety-first culture...”
Source: From an update by Boom as their XB-1 successfully completed its fourth flight on September 21, 2024, at the Mojave Air & Space Port in California. It lasted 48 minutes and reached a top speed of Mach 0.617, along with a maximum altitude of 16,150 feet.