See:
http://www.tgdaily.com/content/view/32508/113/

Woomera (AUSTRALIA) – A scramjet fired Friday in southern Australia briefly hit speeds of ten times the speed of sound. The engine was boosted 330 miles into the air and hit 6800 miles per hour on the way down, fast enough to go from Los Angeles to New York in about 25 minutes.

The entire flight lasted 12 minutes 15 seconds with the scramjet sitting on top of a fairly conventional rocket for much of the ride. The rocket had two stages with the first stage dropping off after six seconds. The second stage took the scramjet into space. Scramjets must first be propelled to supersonic speeds before igniting since it rams (like its name suggests) atmospheric air into hydrogen fuel. The advantage of such a design is that scramjets don’t need to carry as much fuel and can have relatively few moving parts.

The scramjet was developed as a partnership between the American Defense Advanced Research Projects Agency and Australia’s Defence Science and Technology Organisation. Both groups hope to do at least ten more flights in five years.