The YF-23 “Black Widow II” was a stealth technology demonstrator and prototype fighter developed by Northrop/McDonnell Douglas in the late 1980s and early 1990s for the U.S. Air Force Advanced Tactical Fighter (ATF) program. The PAV-1 (Prototype Air Vehicle 1) was the first YF-23 prototype, featuring a stealthy airframe, advanced aerodynamics, and supercruise capability designed to compete with the Lockheed YF-22. Although the YF-23 demonstrated impressive speed, stealth, and manoeuvrability, the YF-22 was ultimately selected, becoming the F-22 Raptor, while the YF-23 program ended after prototype testing.