From: Upstate New York
There are a dozen air HQs in the Japanese OOB more or less in the early war, plus all the command HQs on top.
How many do you need? Thats loads. You're essentially swapping the scarce resource of level 4 airfields in WITP for the scarce resource of air HQs in AE (not so scarce at all, in fact, when you consider command radii).
I'm more receptive to the supply argument which might at least be in an issue in some CENTPAC island chain, but somewhere like, say, Malaya, or Burma, or Java, or even Timor, thats practically a non-issue.
A dozen? Try 5 that are at all usefull. You've got the 11th Airfleet and the 21st, 22nd, 23rd and 24th Air Flotillas (and based on initial location, the 24th is basically useless). So, you've got 4 Air HQ's and the Southern Army Command HQ. That's all. On top of that, the Air Flotillas can only handle one base at a time (range of 1 hex). So, three of your five HQ's can only deal with a single air base. The other only has a range of 3 or 4, so its also not terribly useful. The Southern Army HQ then is the only really useful one. When you said a dozen, I assume you're including the ones permanently stationed in the Home Islands or the China Theater. For all practical purposes, these are useless until the allies come knocking on the door of Tokyo.