Some callsigns are in the format (Something) "(Number)-(Number)". Other callsigns are in the format of one word, such as the famous examples of Pete "Maverick" Mitchell and Bradley "Rooster" Bradshaw. At what times are these callsigns used?
Section 2-4-20 of the 7110.65 describes how callsigns are to be used.
Tactical pilots of the US Navy and Airforce commonly give each other "callsigns", but they are actually just nicknames. They are used only for inter-flight communication with other pilots on discrete squadron frequencies. They are not used with ATC.
$\begingroup$ Ok, so here's what I think you meant: Take the example of a YouTuber and EA-18 pilot with the callsign "Pail" in VAQ-139. On the squadron frequency other squadron members would call him "Pail" but everywhere else he's just "Cougar (Number)-(Number)". $\endgroup$ Feb 17 at 4:01
$\begingroup$ Something like that, yes. There are two possible definitions for the term "callsign:" 1) a nickname and 2) a formal identifier used by/with ATC. (See also my answer here.) $\endgroup$ Feb 17 at 4:09
$\begingroup$ @JustACoder, yes, that's exactly what I meant. Cougar in this case is their assigned squadron call sign, the number is generally the mission number per the flight schedule, but it may be the side number of the aircraft. $\endgroup$ Feb 17 at 6:09