During my thru-hike, I “observed” that more hikers used air mattresses than foam. No hard numbers, but I would guess like 70-30, remembering pads laid out in shelters.
People obvioulsy make it to Katahdin with either, and as Joe mentioned, the important thing is that the pad you choose “aids” you in getting sleep. If you don’t sleep well, figure out why, and fix that.
If you have been hiking with cell foam and have one, start with that. There are plenty of outfitters early in an AT thru-hike so you can always change to an air mattress if you find you can’t sleep comfortably due to the foam cell pad.
Like I mentioned, this is simply my observation/opinion, no study.
Bison