Currently fuel is never an issue, the investment to hit the refinery and then the base fuel depots does not bring nearly enough reward. At worst you get planes down to 75% fuel load. With the current fuel burn rates even planes like the LA-7 can take off and fight comfortably at another base. The only thing you are really doing is restricting forward bases from drop tanks, but no plane in the game needs a drop tank from a forward base anyway. Air Warrior used to degrade the fuel instead of limit it, that would be another rewarding option. If you want the top of the line fuel you need to repair your base or take off further back, etc.