NASA's incredible X-plane that is shaped to muffle the sound of its sonic boom has been cleared for assembly by a management review ahead of test flights in 2021. Dubbed the 'son of Concorde' after the Mach 2 airliner, the X-59 Quiet SuperSonic Technology (QueSST) is NASA's first large experimental plane in three decades. The X-59 will cruise at Mach 1.42 (1,090 mph/1,754 km/h) and is designed for supersonic flight while preventing its sonic boom from being heard on the ground. If successful, the craft could one day travel from London to New York in just over three hours, while...