Back in 1976, at the height of the Cold War, one of America's most secretive planes, the SR-71 Blackbird, managed to achieve a tremendous feat: it traveled at a speed of Mach 3, which is 2,193.2 mph ...
Rotating Detonation Engines (RDE) have been flown by Venus Aerospace. They use continuous detonation waves for propulsion and provide 15% efficiency gains (in specific impulse or fuel consumption) ...