My aunt will be traveling with us and will be bringing along her own portable concentrator. I believe it is an Ellipse (spelling?). With the airlines she is required documentation of some sort from her doctor. Does Carnival require the same? We tried asking customer service but their answer back was confusing. It sounded that if we had to use liquid that it would have to be delivered by an approved company but if we used our own portable that no paperwork was needed but we are not sure. Does anyone know?