I am a home care Respiratory Therapist and my in-laws travel with a CPAP and a BIPAP machine. It is so common now for people to travel with some kind of sleep therapy device that I don't think you would have any problems. Just make sure you are prepared to take the unit out of its carrying case at the airport/cruise port for inspection. That was the only time anyone wanted to look at the units when we went on our cruise almost a year ago and no one asked for any documentation.
I definitely agree with the suggestions of taking your own extension cords because plugs are at a minimum. Also, you probably already know this but make sure you dump out all of the water from your machines before packing them up to go anywhere and that they are completely dry!! You'll save yourself the hassle of getting them repaired from water damage later.
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