The title of the fastest jet ever built belongs to the Lockheed SR-71 Blackbird, which holds the official world record for a sustained flight by a manned, air-breathing jet aircraft. In July 1976, the SR-71 reached a blistering speed of Mach 3.3 (approximately 2,193 mph or 3,530 km/h) at an altitude of 85,069 feet. The Blackbird was so fast that its standard evasive maneuver for a surface-to-air missile was simply to accelerate and outrun it. While the rocket-powered North American X-15 reached Mach 6.7, it was not a "jet" in the traditional sense as it did not use atmospheric oxygen for combustion. In the modern era, the fastest active combat jet is the MiG-25 Foxbat, capable of reaching Mach 2.83 in short bursts, though doing so risks permanent engine damage. Looking toward 2026 and beyond, experimental "scramjet" technology (like the X-43A) has reached speeds of Mach 9.6, but these remain unmanned test vehicles. For a manned, operational jet, the SR-71's record remains unbeaten nearly 50 years later, representing the pinnacle of Cold War-era titanium engineering and high-altitude surveillance technology.