Gas is overpowered, and how the hell are you supposed to do 1948 without taking even one shot? Needs MP, a skirmish mode, and more types of planes. I could see it becoming something akin to a harder version of Battalion wars.
As much as i like the game, it falls into a bad trend along with many other game. It is incomplete, and the only way to have it full is buying it. Spending $20 on a flash game? Not my idea of fun. For what it is, it's fine. Though, a disappointment that the full version looks great.