In CivII you could do as much with the air-force as the army. In CivIII, you could hardly do anything! I think that in CivIV, they should restore the flexibility of being able to move the air units all over the map and so-on. This would be really cool. You should also be able to carry nuclear missles in certain airplanes so that you can bomb anywhere and not be restricted to keeping the missles in the city they were created in, especially if it is an in-land city that can't load nukes onto submarines.