
An aviator call sign (alternatively aviator callsign or, to differentiate from general civilian uses, military call sign or air force call sign) is a call sign given to a military pilot, flight officer, or enlisted aviator. It is a specialized form of nickname that is used over radio communications as well as a substitute for the aviator's given name, and is often displayed on name tags and on the aviator's assigned aircraft, usually on the fuselage or canopy rails.
Call signs are most commonly used in air forces and naval aviation by fighter pilots and pilots of combat aircraft (i.e. fighters, attackers, multiroles, bombers), as well as in some army aviation by military helicopter pilots (usually attack helicopter pilots), though they may also be used by other military aviation units such as transports, maritime patrol, and electronic-warfare aircraft. Many NASA astronauts with military aviator backgrounds are also often referred to during spaceflights by their military call signs rather than their first names. Call signs may be used in non-military contexts and organizations as well, such as in aerobatics, police aviation, or aerial firefighting.
The origins of aviator call signs are varied. Some call signs play on or reference variants of the aviator's given name, surname, or middle name. Other inspirations for call signs may include personality traits, personal appearances, references to historical figures or popular culture, shared events, past exploits during the pilot's career, or the pilot's own personal history. Some call signs are derived from embarrassing situations or negative traits, and may come off as derogatory or insulting, though these are usually (but not always) intended as banter-like in origin.
In almost all contexts, aviator call signs must come from members of the aviator's squadron, flight training class, or other cohort. It is considered bad form to try to give oneself a call sign, especially if it is considered self-aggrandizing. If aviators complain about a call sign they are given, especially if it is fairly derogatory, the more likely it is to stick.
Some aviators use the same call sign throughout their careers; in other cases an aviator might have a series of call signs. For example, U.S. Navy Lieutenant Kara Hultgreen was originally given the call sign "Hulk" because of her ability to bench-press 200 pounds. Later, after a television appearance in which she wore noticeable makeup, she received the call sign "Revlon", and a 1998 biography was entitled Call Sign Revlon.