Ehm this is not really accurate. Not many people use a BiPAP machine. They're only for very old people who have serious difficulties breathing. A BiPAP machine can serve a largely different pressure for exhaling and inhaling, a normal CPAP machine can only do that with about 2cmH2O difference which isn't a lot. But normal people have no issue exhaling against the output of a CPAP anyway so it's not a problem.

For this reason BiPAPs have much more beefy motors so they can ramp up and down quickly. Or perhaps two separate motors, I have never taken one apart (I have normal CPAPs which is basically just a pressure fan in a box with some regulation electronics)

But anyway my point is, a normal CPAP doesn't use that much power. It may use more than that if a humidifier is used (which is probably not a bad idea on a plane, but it requires distilled water which is an issue to bring on the plane in sufficient quantity). Because the humidifier is just a heater and heaters use lots of power.

I don't use a humidifier, my CPAP has a PSU of about 60W but I doubt it uses more than 20. The problem is more that they are not USB-C powered, nor are there official USB-C converters for it. I could probably construct one but bringing home-built electronics on a plane is probably not a great idea either.

So yeah I don't think this will be a great option tbh. If power is provided on the plane it would work but I've never seen this on my flights except in business/first.

Sorry, my bad - regional availability and cost were the challenge, not BiPAP-ness. A Luna TravelPAP looks 20 W max and there's a USB-C cord. Heat and humidity is separate - a disposable sponge.

Given 100Wh batteries, I've wondered if one could kludge a TSA-compatible carry-on electric mobility device, like skateboard wheels plus selfie sticks, as a one-bag travel scooter. My hungry laptop already needs several. Or carry a conversion kit for an "amazon, use, then give away" inexpensive manual kick scooter.