It was on, Joel.
I checked after a few turns, because I was surprised that there wasn't any (those nice, reassuring red lines on the map during the combat resolution sequence).
I even tried allocating some GA directives manually later in the scenario (on Kharkov units specifically), but they didn't happen either.
It will be interesting to see msf567's AAR to find out, if he experiences the same issue (assuming that he's got AI switched on for the air war, as I did).
the AI-assist has a couple of things to watch out for:
a) make sure its allocated to the relevant command, usually best to hook to the Pzr Grp, that will keep the planes up at the front etc
b) the AI-assist is very supply aware and won't place planes on poorly supplied airbases regardless of (a). This is actually useful but can leave you without air cover.
The solution lies in your overall logistics system.
In general its hard to keep the LW up with the front in the Ukraine. its the one sector where the front can move rapidly and you can get a long way from your railheads and working depots
I changed Fliegerkorps IV to follow PG1, but I would need to check the supply situation again.
Luftflotte 4 was set to Supply Priority 2, IIRC, and I only changed that later in the scenario, so perhaps supply was the issue, as supply in general was for the whole force.
I'm wondering how on earth it's possible to achieve all the objectives with the rapid territory gains and resultant supply issues that you outline and that I experienced.
Hence why I'm interested in how others approach this, because in 17 turns I don't see what can be done to ameliorate the logistics challenges.
It feels as if I'm pushing water uphill