An experimental aircraft that could fly from Sydney to London in less than an hour at blistering speeds of 20,921km/h is due to be tested this week.

The unmanned, arrowhead-shaped aircraft, dubbed Falcon Hypersonic Technology Vehicle 2, will test new technology that would provide the US Pentagon a lightning-fast vehicle capable of delivering a military strike anywhere in the world in under an hour.

The Falcon Hypersonic Technology Vehicle 2.

At its top speed it could travel the 17,000 kilometres between London and Sydney in about 49 minutes.

The Falcon is part of Lockheed Martin's "prompt global strike" concept. It is being funded by US Defence Advanced Research Projects Agency, or DARPA.