"scm" wrote in message
...
The reason I am asking is that I have to use a CPAP machine to breath
while I sleep, (Continuous positive air pressure) for sleep apnea. I am
contemplating a trip to Hawaii where I will have to sleep during the
flight. Issues about whether I can power my equipment asside, I would need
to know what my effective altitude is to know how to set up my CPAP
machine.

I've heard it's about 6,000 feet, though another poster has mentioned 8,000
and it sounds like they've done more research than me. My reason for
posting, though, is to say that I'd thoroughly recommend talking to the
airline(s) you're thinking of flying with. I'm sure they come across
instances like your own from time to time, and will be able to answer all
your questions not just with regard to what altitude to set but also
concerning the logistics of boarding your equipment, powering it, etc.

D.