Northrop Grumman YF-23
The Air Force pitted the YF-23 against Lockheed’s YF-22 during the Advanced Tactical Fighter competition, and the winner would eventually replace the aging F-15 Eagle. Both prototypes performed well when they took to the skies in late 1990, but the YF-23’s radical design elements would be even more expensive than the F-22 Raptor, which costs a whopping $143 million per plane.
