The Aurora aircraft is allegedly a secret U.S hypersonic (Mach 5 or greater) spy plane developed in the 1980s or 1990s as a replacement for the aging and expensive SR-71 Blackbird. Aurora aircraft might be based at the secret government airbase Groom Lake (Area 51) in Nevada, as well as Edwards AFB, California, and Machrihanish, Scotland.
While the United States government denies Aurora's existence, many people have pieced together sketchy evidence to the contrary. The strongest sources lies in a possible eyewitness and trained aircraft spotter named Chris Gibson. In 1989, while working as an engineer on a North Sea oil platform, he saw and drew a picture of an unfamilar triangular-shaped aircraft. Also, some cite Aurora as the source of several unexplained sonic booms that occurred over California (especially Los Angeles) and Nevada.
The triangular craft is rumored to have an unconventional methane-powered propulsion system - possible reports include pulsing sounds on takeoff and a contrail which looks like "doughnuts on a rope".
