“Oxcart” was an odd nickname for the plane that killed pilot Walter Ray. Oxcarts are slow, cumbersome, and old. Ray’s A-12 jet, meanwhile, was fast, almost invisible, and novel. Among the US’s first attempts at stealth aircraft, it could travel as quickly as a rifle bullet, and fly at altitudes around 90,000 feet. On a radar screen, it appeared as barely a blip—all the better to spy on Soviets with—and had only one seat.

On January 5, 1967, that single space belonged to Ray, a quiet, clean-cut 33-year old who spent his workdays inside Area 51, then the CIA’s advanced-aviation research facility. Set atop the dried-up bed of Groom Lake in the Nevada desert, the now-infamous spot made for good runways, and was remote enough to keep prying eyes off covert Cold War projects. On the books, Ray was a civilian pilot for Lockheed Martin. In reality, and in secret, he reported to the CIA.

https://www.popsci.com/story/technology/lost-cia-spyplane-area51/