New hypersonic jet Might reach Mach 5 to Mach 10.

The video I saw doesn't have much detail, but it does say the system under development by the Airforce, NASA and others uses 1000 explosions per second in its engines.

Fifty-seven years after combat pilot Chuck Yeager broke the sound barrier, NASA will make a second attempt Saturday at flying an aircraft at 5,000 mph -- about seven times Mach 1, the speed of sound.

The space agency's dogged pursuit of extreme speed, officials hope, will ultimately make space flight easier to accomplish.

NASA will roll out the X-43A, capable of reaching speeds more than Mach 7, in a test flight over the Pacific Ocean. The Hyper-X, as it is called, could also give rise to commercial planes that zip passengers between London and New York in less than two hours.

"It's relatively simple in its concept," said Griff Corpening, chief engineer for the X-43A program. "It's incredibly challenging in its execution.... [That is] where 40 plus years of research comes in."

The $250-million Hyper-X program has already attracted the interest of the Air Force and private aerospace companies such as Boeing. But dreams of civilian spin-offs are at least 20 years away, said NASA officials, who are betting the program will first lead to a more durable, cheaper workhorse for the space fleet. - cnn

A commenter on this story on gizmodo writes:

Mach 10 = 7,612 MPH
Distance between New York and Los Angeles: 2,451 miles. So you could get it across the country in about 20 minutes