An aviator call sign or callsign is a nickname given to a military pilot or other flight officer. This call sign is a substitute for the officer's given name, and is used on name tags, planes, and radio conversations.

The etymology for an aviator's call sign is varied. Most call signs play on or reference on the aviator's surname. Examples (taken from Top Gun credits) include

• Lt. Rick 'Curly' Moe (a Three Stooges reference)
• Maj. Ray 'Secks' Seckinger
• Lcdr. Thomas 'Sobs' Sobieck
• Lcdr. Robert 'Rat' Willard
• Lcdr. C.J. 'Heater' Heatley
• Lt. Ricky 'Organ' Hammonds (a reference to a brand of organ)

Other inspirations for call signs, using examples from characters in Top Gun or from a book (ISBN 0879384425) with a chapter on the subject:

• A personality trait, such as Tom Cruise's character Lt. Pete 'Maverick' Mitchell (or an inversion of a character trait, such as Mark Hamill's character Col. Christopher 'Maverick' Blair).
• Cdr. Theodore 'Spuds' Ellyson, the first United States naval aviator, whose nickname was later used for aviators who had or came close to a ramp strike near a ship's spud locker
• Cdr. Wright "Wilbur" McLeod, a historical play on the aviator's given name
• Douglas "Wrong Way" Corrigan, who was a private aviator, but illustrates how call signs can memorialize events which the aviator may prefer to forget
• call signs might include pop cultural references (a pilot with the surname Winfrey might get the call sign Oprah )

Aviator call signs nearly always must come from a member of the aviator's squadron, training class, or other coworker. Some stick with the aviator forever, while in other cases an aviator might have a series of call signs throughout his or her career.