Thinking about this, I think that Exalted would be the best choice, as there's a definite fit. It'd most likely be a Solar Game, featuring Warstriders- and larger, so much larger vehicles- primarily. I think that there'll be plenty of things about the game which'll make it well-suited towards this. The experience style'll most likely be explosive- Characters start pretty standard, but experience will be extremely generous, training times extremely short, etcetera. I'm thinking of ways to work with the vastly differing sizes of vehicles- I'm currently looking at something along the lines of, if there's a difference of 1 'class', the smaller one uses human-level stats, the larger one Warstrider level stats. Any larger than that, and the larger one is, essentially, viciously hostile terrain.
If I were to end up running this, which seems overly likely, then the thing I'd want to do most is make sure that I have a good outline for the path that things will take.