Summary and 3 Points You Need to Know: The YF-12A, developed by Lockheed Martin’s Skunk Works in the early 1960s, was a pioneering aircraft that combined early stealth features with unmatched speed.

The aircraft made its last flight on Apr. 11, 1976 and was removed from flying status on Jun. 24, 1976 with only 556.4 flight hours, not including the 180.9 hours accumulated on the aircraft as YF-12A ...