"Puffy Ack" was more of a "Curtain Ack" in real life. The fuses where pre set to match altitude and what the standard practice was to set "curtains" of ack in front of a formation of flyer's and they would fly through it with the shells fuses set on timers, IE to blanket a set altitude.
Later came Radar aided and fire control Ack with the shells actually having proximity fuses, but most where duds, but still proved to be more effective than the previous method.
All in all, a wall of lead and shrapnel is a wall of lead and shrapnel. You will have your best success at flying airplanes made of metal, going fast, changing altitude and avoiding straight lines so not to help the radar and proximity fuses. Also going in on a CV with 20 other airplanes was more effective in the real world than going in as THE ONLY TARGET. So keep that in mind.
If Ack was to get anymore civilized in this game, CV's wouldn't stay up very long now would they.
And most ground bases where not heavily protected with AA, Radar simply gave enough advance warning to get aircraft up in the air to defend it, and the guns where busy protecting non moveable assets, like factories and the voting public (cities).
For Carrier Groups, Cities and Strategic implacements, Radar was pretty common post 43, but your mobile AA (small caliber through mobile 88's) where simply spraying and praying on the battlefield (which is not modeled in this game except through our GV's and Trains). The Field Ack I am guessing is simply the case of small caliber through 20mm getting you in a crossfire.
Personally, Paper Airplanes and Large Slow aircraft present bigger targets. LA7 vs a P47 or 38 are obviously two different types of bullet magnets.