Air Force test pilot Chuck Yeager, flying with two broken ribs from a horseback riding accident he kept secret from his superiors, pushed the Bell X-1 to Mach 1.06 at 45,000 feet. The rocket plane, nicknamed 'Glamorous Glennis' after his wife, was dropped from a B-29 bomber before firing its engines. The flight proved supersonic flight was survivable and controllable, opening the door to the jet age.
Yeager had cracked two ribs falling from a horse just two days before the scheduled flight, but he feared being grounded and told almost no one. He rode to the plane in visible pain, sawing off a length of broomstick so he could lever the X-1's hatch closed with his weakened arm since he could not reach up properly.
The orange bullet-shaped X-1, modeled partly on the shape of a .50-caliber bullet, was carried aloft under a B-29 Superfortress and dropped over the high desert near Muroc Field, later Edwards Air Force Base. Yeager fired its rocket engines and climbed to 45,000 feet, pushing past what engineers had feared was an impenetrable wall of turbulence and drag.
At Mach 1.06, he heard something like a distant sonic boom rattle the ground below, though inside the cockpit the ride actually smoothed out once he crossed the barrier. The flight was kept classified for nearly a year, but when revealed, it made Yeager a legend and confirmed that aircraft could be built to fly faster than sound, reshaping military and eventually commercial aviation.