The Mikoyan-Gurevich MiG-15 (Russian) was a jet fighter aircraft developed by Mikoyan-Gurevich OKB for the Soviet Union. The MiG-15 was one of the first successful jet fighters to incorporate swept wings to achieve high transonic speeds. In combat over Korea, it outclassed straight-winged jet day fighters which were largely relegated to ground attack roles, and was quickly countered by the similar American swept-wing F-86 Sabre. The MiG-15 is often mentioned, along with the North American F-86 Sabre, as the best fighter aircraft of the Korean War, and among the best fighter aircraft of all time.