If NASA’s bet on its newest X-plane pays off, the long-nosed aircraft could revolutionize commercial aviation. That is, if ...

Subsonic - anything below the speed of sound; such as current passenger airliners Supersonic ... bigger with hypersonic flights. They'd be even more expensive and also cause a sonic boom.

More than half of sonic booms in the UK between 2013 ... the "ongoing development of new aircraft types capable of supersonic and hypersonic speeds". It said following feedback it would "proceed ...