What was the damage level at PM?
Couldn't say for sure, but it couldn't have been much if any. I made it a point to fly or ship in extra engineer units from the get go, for example those that start out in Brisbane and Cairns, so recovery would have been quick. In any event a dozen or so Bettys every other turn hardly made an impression.
Was it over it's ac capacity?
Again, couldn't say. IIRC, It was a level 4 field with both the 111th and 113th base forces, which put the aviation support points up around 250+. As far as squadrons, I had both P-40s, a P-400, the Hudsons, the A-24s and both B-25s.
Did you forget to bribe the AI not to screw you?
I made sure to switch the AI's morality level from "Chicago Politician" to "Mother Teresa" prior to the game.