On Island Alpha Medical can order portable oxygen machines or help. My husband has been on oxygen for years. He uses an OXYGONET machine. That is the same as an INOGEN machine. He uses the Inogen One. It goes to a setting of six liters. I don't know how many your wife needs (or will need) as time progresses. We are looking at buying another Inogen to take as a back up. They use the same batteries as the OXYGONET, You will also need permission to fly with the machine. You can download the form from Delta and send it in. Turn around is quick. I always take the completed form with me. You have to check in personally to fly. You can't print your ticket. Also, going thru TSA can be a bit of a pain as they take every thing apart. We have learned to take a small carryon with all his equipment on top. I hope this helps. It may seem a little confusing at first, but it is a life saver! Safe travels Alsmost forgot: depending on your wife's number of liters will determine how many batteries she will need to carry with her. We always have 6. (and we keep them charged when on island. )