DARPA’s goal is to create an aircraft capable of reaching any target in the world in less than an hour.

The triangular wedge of zoom known as HTV-2 is capable of reaching Mach 20 – approximately 13,000 miles per hour – according to DARPA. At such speeds in Earth’s atmosphere, friction subjects the vehicle to temperatures of more than 3,500 degrees Fahrenheit.

As DARPA said on the HTV-2 site, at that speed “air doesn’t travel around you – you rip it apart.”

http://security.blogs.cnn.com/2011/08/11/new-york-to-la-in-less-than-12-minutes/?&hpt=hp_c2