Wingman

A wingman (or wingmate) is a pilot who supports another in a potentially dangerous flying environment. Wingman was originally the plane flying beside and slightly behind the lead plane in an aircraft formation.
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.