Fighter aircraft rarely spend all that much time operating at their top speeds. However, analyzing the top speeds of different fighter aircraft can still tell you quite a lot about an aircraft’s design priorities. On paper, the F-15 Eagle family is clearly quicker than the F-35 Lightning II, both of which are fighter programs originally developed for the United States Air Force by McDonnell Douglas and Lockheed Martin, respectively. The USAF lists the maximum operational speed for the F-15 Eagle at around 1,875 miles per hour (3,017 km per hour), which accounts for a speed of roughly Mach 2.5 at altitude. The F-35 Lightning II is capped at a top speed of around Mach 1.6 at altitude, which computes to around 1,200 miles per hour (1,931 km per hour).