We fly with a neb and a lot of meds. As pp have said the you will have no trouble with the TSA, just be sure that you tell them at the front of the line that you have a medical device and any medications that you need to declair ( this makes it go a little smoothe). You will have to take it out so be sure it is in a easy to reach place. In order for medical items to not count toward your carry on allowance they must be in a bag alone. You could carry your neb, the meds for it and any other RX or OTC meds that you need and it will all be medical, but if you out a book or other non medical items then it will count.