F-15 and F-16 are two fighters that came out of programmes started after the Vietnam war demonstrated clear inadequacy of BVR-only designs then in service. When it became obvious that high agility is a necessary characteristic of modern fighter aircraft, F-15 project was revamped in order to give it better agility. LWF project was also started, and resulted in F-16 and F-18. F-16 was designed around John Boyd’s energy maneuverability theories, with low drag and high sustained turn rate. However, USAF did not want a dedicated dogfighter, especially since it could steal light from high-cost F-15; as a result, they turned F-16 into a multirole platform despite it being far less suited for the role than the F-15 (which was later acknowledged with the F-15E). This led to weight increases and loss of maneuverability. Currently, main variants in service are F-15C and F-16C, and these two will be compared by default, unless noted otherwise.