It is air yes....its not necessarily a problem but if he isnt getting enough at each feed because he is taking in air you'd need to feed more often.

it can be difficult to feed without getting too much air in their crops...what are you using to feed him with?

you could try using a syringe but you must be very careful as if he is not ready for his food oorrr you press the plunger too quickly the food can go down his wind pipe.