It would be good to have a check for who chunks are loaded for. If a chunk is loaded only by one player then when a player logs out while flying, the plane is paused in the air. Obviously if other players are in the area then the plane will not be frozen.

This feature would fix the problem where when players log out, are kicked or on server restarts the plane flies away and the player falls to their death.

This bug is present with 2.0.3 Flans Mod

Closing this, plains seem to logout with the player now. 2.3.1