A wingman (or wingmate) is a pilot who supports another in a potentially dangerous flying environment. Wingman was originally a term referring to the plane flying beside and slightly behind the lead plane in an aircraft formation.
According to the U.S. Air Force,
The traditional military definition of a "Wingman" refers to the pattern in which fighter jets fly. There is always a lead aircraft and another which flies off the right wing of and behind the lead. This second pilot is called the "Wingman" because he or she primarily protects the lead by "watching his back."
The wingman's role is to add an element of mutual support to aerial combat. The presence of a wingman makes the flight both offensively and defensively more capable by increasing firepower and situational awareness, permitting the attack of enemies, and increasing the ability to employ more dynamic tactics.
Colonel Robert Smith provides an extensive description of the work and role of wingmen during the Korean War. Among the wingman's primary responsibilities are remaining close to the leader of the aerial formation and warning the leader of any immediate threats at the cost of losing mutual protection. Smith describes the responsibilities as mutually exclusive; never losing the leader required attention in front of the wingman, but warning the lead of any aircraft threats meant focusing on the rear. The wingman needs to protect the leader and react constantly according to his surroundings and movements. Smith describes the difficulties of flying under poor visibility and the trying effects on human perception under such conditions, especially considering the danger of being separated from the leader of the formation. According to Smith, wingmen are expected to remain with the leader, even at the cost of scoring an easy kill.