One of the most successful and widely exported Soviet designs, the MiG-21 (NATO reporting name FISHBED) is a lightweight fighter aircraft, optimized as a short-range interceptor. It had a limited ground attack capability, but usually was used in air defense, carrying two air-to-air missiles and droppable fuel tanks. As with the F-4 Phantom II, the original version did not have an internal gun, but later models had a 23mm cannon.
A copy, with independent improvements, was made by the PRC, as the Chengdu J-7 (fighter). J-7G aircraft are still in combat roles for the People's Liberation Army Air Force (PLAAF), where they do ground attack as welll as point air defense.
During the Vietnam War, it was first encountered in combat by U.S. fighters, it became evident that American training did not adequately address air-to-air combat. U.S. programs, including Top Gun, soon included instructors flying aircraft with comparable agility such as the A-4 Skyhawk and F-5 Tiger. The instructors followed MiG-21 tactics.
The aircraft has been exported to many countries, where it is still operated, sometimes as a second-tier fighter if the opponent has more advanced aircraft. Still, it can be a capable aircraft when flown by a good pilot.