So I managed to tear my ROHO air mattress, which is the same neoprene rubber material and construction as the popular wheelchair air cushions. The little patch kits that came with it didn't work at all, and also tried a bicycle inner tube repair kit that didn't work either.
But what has worked well so far is a product called "seal cement" by McNett. It is described as a industrial-strength neoprene cement. I purchased it from a local scuba supply company. I bought a new cheap bicycle inner tube and cut a small area out of it to use as a patch over the tear.