I don't make much use of it except in very late game land wars. Theoretically I could pack 20+ fighters on a bunch of carriers and that would be more efficient, but I usually wind up just spamming marines/destroyers/battleships on water maps. 10 destroyers and battleships make it very hard for the AI to do anything, and enough marines will overrun the AI's cities, which are invariably poorly garrisoned as you can change targets or even attack multiple cities per turn.
Land wars I'd place higher priority on them. While your troops march at late game enemy cities they have a tendency to get enemy air damaging them. Also, siege at that point is much easier with air than ground forces (tanks and planes come way before mobile artillery, and you can have defenses off before you get there). I seldom bother with air as the game is usually over by then. If it is not, then I tend to use fighters and to a lesser extent bombers, they're actually not that expensive to produce.
Hell, in a couple games I've ignored all that and just had 2 cities crank guided missiles. Those are extremely fun.