As you saw a video scene after beat 2nd stage at the arcade, your plane will refuel at refuelling tanker exactly on top of monument map. It actually exist for solo flight where you can refuel by yourself, but you must flight precisely and synchronize with the tanker in order to refuel in the air. Here where you need to find the tanker, it actually pretty easy for any beginner. enter the game (which is in monument map) with either US fighter or Japanese one then look up with the right stick. You'll find up a dot lingering above the sky which is actually a KC-135 tanker aircraft. Now, about the refuelling part where it is not explained by the instructor at the training mode ill tell it by myself. First, approach the aircraft approximately 1000m from you while try to climb up. Put the throttle at 100% but dont engage any afterburner(if youre a land based fighter) Second, if you think you already closer beyond 1000m, slow down your aircraft carefully without releasing any airbrake to 400kt. This shouldnt give you a sudden brake that you will might be lag by it. Third, approach the tanker once again with speed decreased to 350kt. Once you approach very close to it, your fuel valve will automatically activate. Fourth, line up your aircraft with the tanker precisely. It principts it same as landing while this one is predict the range of your fuel dock valve and the height of the tanker exact. And the last step, attach the fuel valve onto the tanker refuelling valve. I recommend to turn on the cockpit mode for better vision. And try to dont make any sudden move while lining up your fuel valve onto the tanker refuelling hose/pipe. Once you have done attach the fuel valve, youll soon hear a confirmation voice and your aircraft fuel will start to fill up immediately.