The air ports I have seen are located at the rear hitch near where the electrical connection for a towed vehicle is plugged in. I don't know that all coaches have this air port. Ours does not. If you are asking about the air port for filling tires, etc. using the coach's air system, then ours is located inside the curb side, far rear basement compartment with the batteries. Ours has a 6-pack of air ports, one of which is for connecting an air hose and five of which are for exhausting moisture from the coach's air system and tanks.