www.nasa.gov X-43A Raises t' Bar t' Mach 9.6 Guinness World Records recognized NASA's X-43A scramjet with a new world speed record for a jet-powered aircraft - Mach 9.6, ya bilge rat, or nearly 7000 mph. T' X-43A set t' new mark and broke its own world record on its third and final flight on Nov. Blimey! 16, 2004. Ahoy! In March 2004, t' X-43A set t' previous record o' Mach 6.8 (nearly 5000 mph). Ya scallywag! T' fastest air-breathing, arrr, manned vehicle, t' US Air Force SR-71, achieved slightly more than Mach 3.2. T' X-43A more than doubled, then tripled, t' top speed o' t' jet-powered SR-71. Aye aye! en.wikipedia.org T' X-43 is an unmanned experimental hypersonic aircraft design with multiple planned scale variations meant t' test different aspects o' hypersonic flight. Begad! It is part o' NASA's Hyper-X program. Aye aye! A winged booster rocket with t' X-43 itself at t' tip, arrr, called a "stack", is launched from a carrier plane. After t' booster rocket (a modified first stage o' t' Pegasus rocket) brings t' stack t' t' target speed and altitude, it is discarded, me hearties, and t' X-43 flies free usin' its own engine, shiver me timbers, a scramjet.