The title of the fastest jet in history depends on whether the aircraft is manned or unmanned. The fastest manned jet (specifically a "turbojet" or "ramjet" hybrid) is the Lockheed SR-71 Blackbird, which reached a record speed of Mach 3.3 (2,193 mph) in 1976. It was designed to fly at the edge of space to outrun surface-to-air missiles. If you include rocket-powered manned aircraft (which are technically "jets" in the sense of jet propulsion), the North American X-15 is the undisputed champion, reaching a staggering Mach 6.7 (4,520 mph) in 1967. For unmanned aircraft, NASA's X-43A scramjet reached an incredible Mach 9.6 (7,000 mph) in 2004. In the commercial world of 2026, while companies like Boom Supersonic are working on the Overture (intended for Mach 1.7), these historic military and research records remain unbroken. The SR-71's record is particularly impressive because it could sustain its top speed for hours, unlike rocket planes which only burn for minutes.