The Northrop Grumman YF-17 Cobra was a lightweight fighter aircraft prototype designed for the United States Air Force (USAF) in the 1970s. At the time, it was believed that many fighters, such as the F-15 Eagle, were too large, heavy, and expensive to operate. Therefore, as the Auto Evolution Blog highlighted, a lightweight fighter (LWF) was required to be introduced for inexpensive combat roles.