In our previous videos, we have looked at several experimental US aircraft pushing aeronautical limits, but never saw service. The F-15 STOL MTD, the F-16XL, and the F-18 HARV to name a few. But there is one experimental aircraft that stands out above all the others for its cutting-edge design. The Northrop YF-23 was in the competition, head-to-head with the demonstrator version of the F-22, and the Northrop/McDonnell Douglas team came up with a very impressive aircraft.