I found this really cool glitch. It enables you to fly without callsign
Your ATC communication will be like this: Palm Springs tower,ready to taxi.
Steps to recreate
1> Open Live
2> Bring callsign menu
3> Go to General Aviation
4> Set your callsign
Of course it’ll show your callsign to you but it doesn’t say it cause there is no abbreviation for - in the game.