The Bell X-1 Breaks the Sound Barrier Over the Mojave
CONFIRMED87% CONFIDENCEHappened as dated, per en.wikipedia.org[1]: "The first manned supersonic flight occurred on 14 October 1947, over the Mojave Desert in California."
Captain Chuck Yeager, drop-launched from a B-29 over the Mojave Desert, took X-1 #46-062 "Glamorous Glennis" to Mach 1.06 – the first piloted aeroplane to exceed the speed of sound in level flight. It was XS-1 flight number 50.
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