Absolutley nothing!"
Apart from the (mis)quote from Edwin Starr, I want to tell you something that happened to me.
A couple of days ago, I played BM tabletop with three other people. As I was the only experienced player and others varied from played-a-lot-but-long-ago to played-couple-of-times to firs-time, we decided not to use fuel. Planes were A DVII, a DXII, an SE5a and a XIII. I never ever played BM without fuel rules.
My! What a game!Everybody,
everybody enjoyed his plane far far more than usual! What a pleasure is to zoom around at leisure! And the guy on the DVII wasn't the more thrilled, you should have seen the greenhorn on the XIII zooming around!
My point is: BM without fuel is quite a
different game, as it is without special damage and burst length. So I think that introducing a variant (an indipendent flag) "without fuel" is a GREAT idea.
Now comes the other side of the coin: how to avoid endless games? Because I'll tell you: a 1 vs. 1 game with experienced players
would last forever. There are some ways.
1. Ammo. With ammo limit (say 20 boxes, without lewis rules), game limit crawls back.
2. Gane turns number. As we set a time limit for maneuver selection when we set up a game, we can set a turn limit, say from 20 to 40 game turns.
3. No-blood limit.Let's say that, if a game proceeds for, say, 10 game turns without a single shot being fired, the game is over (a little like the "2nd turn not completed" rule, only the game is over, not deleted.
So, that's it. I know it's a gauntlet, and that there
are technical issues with it, but I couldn't resist, as it was a
really new game experience, and with a game that i sure know top to bottom and upside down.

Interesting alternative. I would go for the ammo option. And beside the current setting, the user can choose fire/not fire in his round. The game will be running in a fun way I am guessing.
P.