Each country could have a number of refueling birds depending on the size of the map. These aircraft could be at set altitudes, unable to be damaged, marked on the clipboard map with a distinct color icon, run a flight pattern marked by red waypoints on the map. You would simply fly within close proximity and stay there for say 30 seconds to replenish your fuel in your aircraft. The birds could even be set-up to be controlled by each country like task groups are. The idea isn't some ground breaking thought, but it could add a new dimension to the game.