The F-117 was retrofitted with the ability to fly a computer generated flight plan, which would not avoid radar sites but also adjust the plane's attitude in or

The F-117 was retrofitted with the ability to fly a computer generated flight plan, which would not avoid radar sites but also adjust the plane's attitude in order to minimize the radar cross section. [1] [1] Skunk Works: A Personal Memoir of My Years at Lockheed by Ben R. Rich and Leo Janos (page 101 on my copy) The relevant Wikipedia article also mentions the system, but in less detail: https://en.wikipedia.org/wiki/Lockheed_F-117_Nighthawk#Avionics https://en.wikipedia.org/wiki/Lockheed_F-117_Nighthawk#Avion...