Many campers are 2,000-2,500 lbs so air is fine, if going to a 5,000 rig, then I am no expert…
I have air bags and love them. I can micro adjust and get ride height back to normal easily. Truck rides smooth when unloaded and at 5psi and rides the same when aired up to 60 with camper…
Beware: airbags on the springs (leaf springs in my case) or inside the coils are fine. Airbags set next to the springs on the inside can cause more instability because you are supporting the weight from closer to the middle of the truck rather than at the outer edges.