Officially, the fastest plane ever built is the SR-71 Blackbird, built by Lockheed. It was capable of speeds in excess of 3.3 mach (more than 2,200 miles per hour). It was decommissioned in 1998. No one knows for sure whether a faster plane exists, but many people suspect that the SR-91 -- if it actually exists -- is capable of speeds in 5-mach range, although speeds like that would likely take place outside the Earth's atmosphere. Depends The fastest known jet airplane is the SR-71 Blackbird. However faster aircraft have been flown by the U.S. military. But they are rocket powered and experimental which does not fall into your question of the fastest "jet" airplane. Also FYI the fastest commercial airliner is the Boeing 747-400