The AIM-9 Sidewinder is a short-range air-to-air missile, which means it is shot from an aircraft and is supposed to hit an aircraft. It is heat seeking, which means it locks on to heat. It first flew in 1953, and went into air forces in 1956. It was used during the Vietnam War along with the AIM-7 Sparrow, but was not good. At the time, it would hit only 10-20% of the time, and could be fooled. Sometimes it could lock on to the sun or other bogus heat source and not an enemy airplane.
The problems were later fixed, and the new Sidewinders have a good hitting rate. It is in a lot of air forces. The missile can hit from 11 miles. It is very often on many different aircraft around the world today.