According to foxnews.com, Defense Advanced Research Projects Agency (DARPA ) started flight tests on the U.S. air base in California of a hypersonic aircraft Falcon HTV-2, which is an unmanned aerial vehicle (UAV), able to accelerate to a speed of 21,000 km / h. Originally Falcon HTV-2 takes off in the upper atmosphere using rocket and then includes its own engines. In the current trial seeks to cover a distance of up to 7,500 kilometers. In the case of successful tests, this UAV are going to adopt. How to underline the U.S. military, Falcon HTV-2 will deliver air strikes on any part of the globe in less than an hour, after take off from any air base in the U.S..