However, more exciting than the look and (lack of) sound of the new aircraft are the implications for commercial air travel.
"With the completion of KDP-D we've shown the project is on schedule, it's well planned and on track. We have everything in place to continue this historic research mission for the nation's air-traveling public," said Bob Pearce, Nasa's associate administrator for Aeronautics.
With final checks scheduled for the end of next year, it is hope the first flight will take off in 2021.
The technology would double current cruising speed of a Boeing 787 Dreamliner, from 902 kph to 2179 kph – more than halving flight times.
The X-plane is designed to reduce the 'sonic boom' of breaking the sound barrier to a barely audible thump. This has exciting implications for scheduling and practical use of supersonic aircraft, capable of use over built up areas and reaching more airports around the world.
In the Concorde-era of supersonic flight there were huge restrictions on flight path and speed due to the huge sonic boom created by the aircraft.
The effect of breaking the 1234 kph speed of sound can produce an extremely dramatic shockwave, referred to as the 'sonic boom', which is extremely disruptive in built up areas.
Earlier this month, two supersonic typhoons fighter jets broke the sound barrier while responding to a passenger jet with radar problems over UK airspace. The subsequent boom at 4am set off car alarms, rattled windows and woke up large swathes of north London and led the Metropolitan Police to investigate the source of the noise.