8000 mph plane...

[HongGilDong]

http://en.wikipedia.org/wiki/Aurora_(aircraft)

Pulse detonation engines.

There are people in my boating forum who swear they heard the multiple(8) sonic booms from this plane.

The shuttle gives off only two sonic boom.

[{Ru}EINHANDER]

Runs on Ethanol right?

[{Ru}Zog]

Liquid methane...

"In the highly disputed testimony of alleged physicist Robert Lazar, he claims that during his employ at the mysterious S-4 facility in Nevada, that he briefly witnessed an Aurora flight while aboard a bus near Groom Lake. He claimed that there was a "tremendous roar" which sounded almost as if "the sky was tearing." Though he only saw the physical craft for a moment through the front of the bus, he described it as being "very large" and having "two huge, square exhausts with vanes in them." Upon speaking with his supervisor, Lazar was said to have been informed that the craft was indeed an "Aurora," a "high altitude research plane." He was also told that the craft was powered by "liquid methane."

Bob Lazar has been known to say a lot of things, so it could be hogwash. I'm sure there's a lot of craft being made and tested out there that we know nothing about though.

[{Ru}EINHANDER]

.. and being kept in the hangars and underground facilities...