Dear Staff,
Here goes one very simple idea for the interwar periods (duration between 2 and 5 days): Ace of Aces.
Only fighters of early and mid-war periods enabled.
One map with only six enabled fields, three to each side, far apart but not too far, all indestructable, all uncapturable, ack at maximum level.
One base for American planes, one for British, one for Russian, one for German, one for Italian, one for Japanese. All in, all apart.
No troops enabled.
No strat system.
No bombs or rockets enabled.
Wins the side with best kill/death ratio. The highest scoring pilot wins "Ace of Aces" title.
Simple, isn´t it?