Discord is a free voice/chat software. Can be downloaded as an app or used in a browser.
WWII era aircraft: https://discord.gg/yJaP5Wn
Flightgear FDM School: https://discord.gg/Uyrtsar
Operation Red Flag military FG community: https://discord.gg/ptVapkE
Aircraft Mirage 2000: https://discord.gg/xZ3r2KR
Aircraft Saab 37 Viggen: https://discord.gg/RJTwS9a
Aircraft F-16: https://discord.gg/8RcYnjA
Aircraft Panavia Tornado: https://discord.gg/26rvkr2
Aircraft Jaguar: https://discord.gg/G5q5XYN
Aircraft MiG-21bis: https://discord.gg/bs8xyz3
Aircraft Aermacchi-MB-339: https://discord.gg/vNZ5ZPv
- Furthermore many other Flightgear servers exist, that you may need an personal invite to join. To find them, easiest is to go to the Flightgear server and ask or ask in forums.
Its advised that you create a permanent account, instead of creating guest accounts as some people create duplicate accounts which clogs up the member logs and makes it more difficult to @mention people.