 Armed with two Vympel K-13 missiles (known to US pilots by their NATO designation "Atoll"), the MiG-21 had rapid acceleration, was agile at supersonic speeds and at high altitudes, and significantly outperformed its primary target – the F-105 Thunderchief – in all flight regimes.A small, light fighter, its low wing loadings were excellent for air combat maneuvering and its small size made it difficult to spot even when its adversary was warned of its presence.Typically, the MiG-21 was used in hit-and-run tactics; being vectored by Ground Control Intercept (GCI) to an intercept position to the vulnerable rear of an American strike formation, then executing a missile attack and diving away before fighter cover could intervene.