Boom has been working on the world's fastest civil aircraft since 2014. That effort is getting a shot in the arm courtesy of Rolls-Royce. The two are teaming up to find a propulsion system that will work with Boom's airframe while keeping an eye towards a net-zero carbon future. The 55-seat craft is aiming for a top speed of Mach 2.2, which would cut the flight time from New York to London to 3.5 hours, San Fransisco to Tokyo to 5.5, and Sydney to LA to under 7. While development on the Overture continues, Boom's XB-1 demonstrator prototype is set to be unveiled this October.