In the US AF, callsigns are given to the Pilot, Arms Off or other Flyer.
When a combat pilot is assigned an aeroplane, the Rank, Name and Callsign are stencilled on the aeroplane at the entrance to the cockpit.
In the RAF, the squadron gets a Callsign and each pilot will take a number to suffix the Callsign.
In MSFS, UK players who have 3rd Party Military combat aeroplanes, it is easy to get a callsign.
In aircraft.cfg
atc_airline is where you enter your squadron callsign
atc_flight_number is where you enter your number.
e.g.
atc_airline âPAPAMIKEâ
atc_flight_number â1â
for the leader of a 103 Squadron sortie.
There were many fighter squadrons.
In honour of 103 Squadron Bomber Command âBlack swansâ my Callsign is PAPAMIKE 1.
