The US space agency, NASA, has broken the air speed record by propelling a revolutionary powered unmanned plane to seven times the speed of sound.

The ten-second burst, at almost 5,000mph, shattered the previous record set 28 years ago, and took place earlier this month in a test over the Pacific Ocean.

The four-metre long craft uses what is described as a 'scramjet engine', which can propel planes at hypersonic speeds and was launched from a B52 bomber off the coast of California.

The engine is being designed for space travel and it is hoped a craft built with the prototype engine, called X-43A, would be able to travel so fast that it could power itself using fuel from the atmosphere.

NASA says the flight could revolutionise space and air travel.