We have a flight booked on PA. I read through the carry-on info on the website. It states that you are allowed one carry on, but does not mention something the size of a back pack. Has anyone taken one aboard during their travels? We normally have a carry on each(back pack) and a snorkel bag each when flying other airlines. I'm guessing that we will have to forfeit the snorkel bags and rent fins while on Long Island. Would anyone know a good spot to rent some fins for the week?