A suggestion :)
Background: I'm currently the French late in a game, 4 1/2 turns left. Desperate situation on both sides, terrible losses, bad morale, etc., etc. :) And I just lost Isabelle. Anyway ...
I still have a lot of trucks, 6 I think. And as written, I *must* spend 4 fuel and spares each turn (assuming I have them). This feels a bit wrong to me. I think I should have the choice of spending 0-4 (or maybe 1-4) at my option, accepting the consequences of low fuel.
Why do I feel this way? Because I feel I would be in a better situation if I could just get rid of 4 of my 6 trucks. And somehow that doesn't feel right.
You do have a choice. If you simply do not add Fuel & Spares to the plane loads, then you will run short of it. Just see to it that only 2 F&S arrive each game turn, and that will be what you are able to spend, with the consequences that follows.