Having your friends join you in an arena is easy! If you host a SOLO game, all you need to do is click that option, which will give you a special code that you send to your friends by messenger or voice (if you have them on a channel). Then when they input the code, they will be in the same Free for All arena with you.
Want to fly as a TEAM? Click the TEAM option; then click “Create Team”. You can have up to 3 other players on your team. Send them the 4-letter code to join your team. If you wish to fly with only one wingman, uncheck the last two boxes.