The MiG-21 saw frequent action in the Vietnam War and was one of the most advanced aircraft at the time. However, many North Vietnamese aces preferred flying the MiG-17, due to the high wing loading on the MiG-21's. With high wing loading, the MiG-21 was not as agile or manueverable as the MiG-17. Employing a delta wing configuration, it was the first successful Soviet aircraft combining fighter and interceptor in a single aircraft. It was a lightweight fighter, achieving Mach 2 speed using a relatively low-powered afterburning turbojet, and is thus comparable to the American F-104 Starfighter and French Dassault Mirage III.