I had a group booked with Apple Vacations traveling to Cancun flying USA3000. I had a gentleman who needed to travel with the Inogen concentrator. When we booked him the agent never told us he could not take it. This gentleman feels he has been discriminated against since all the other airlines even Southwest allows this unit to be taken on. This machine has given a lot of people the flexibility to be able to travel more than ever. I have tried to talk with the airlines and Apple but was told they would not bend. In my opinion they do not want these people to be able to use them as a tour company... don't need to worry about that since the group has decided not to use them in the future for travel. This is not the 1st time for them to mess up and it will be the last for us to use the. Description of machine follows. I weigh less than your cat. No more worries about running out of oxygen ever again. No more relying on others for your oxygen supply. And no more deliveries. The INOGEN ONE is the first oxygen system designed to provide unparalleled freedom for the active oxygen user. With the INOGEN ONE, you’ll no longer need separate pieces of equipment for home, portable, or travel use. Best of ll, because it gets oxygen from the air around you, there are no gas or liquid tanks to fill. That means your INOGEN ONE will never run out of oxygen. The INOGEN ONE is made to make your life easier. It’s light enough to carry over your shoulder, and it comes with a cart to roll behind you when you’re on the go. We like to think of it as a “polite companion”... and since it’s whisper quiet most people don’t know it’s running. I’m smaller than your coffee maker It can be battery operated. what makes USA 3000 better than anyone else... We are planning to go further with this discriminating issue.