U.S. Government AirShips Northrup/Grummand B-2 Stealth Bomber flying over the Nevada desert in the early 90s Northrup/Grummand B-2 Stealth Bomber on the runway at Area 51, Nevada. The U.S. Air Force/Northrop Grumman B-2 Spirit is a strategic, long-range, multi-role bomber. Tests show that with its low observable characteristics, the B-2 is the most survivable aircraft in the world. NASA "Hyper-X" Scramjet Program. In Phase I of the Hyper-X program, three 12-foot-long, unpiloted aircraft will fly up to ten times the speed of sound to demonstrate "air-breathing" engine technologies. Each high-flying experimental aircraft will fly once, all within the Western Test Range off the coast of California