Yes, crab apples should be among the easier trees to airlayer.
Not to contradict you Brian. At least in my experience crab apples have been a mother to airlayer. On average it has taken me 3 years to air layer a crab apple successfully. That verse a hornbeam, juniper, or JBP that took me one season. Perhaps its me, but I think they are exceedingly tough and would much rather take large cuttings.
Sorry, didn't mean to imply you shouldn't trust Tom too....lol.