I've been carrying my CPAP with me every time I fly for the past 3 years. I have had no problems to date. TSA now requires that CPAPs be screened by the X-ray machine on a separate tray (like a laptop). I always carry my doctor's prescription for the CPAP with me in the event a newbie TSA screener does not recognize it as such.

My concerns recently have been that of the CPAP considered as carry-on item or a required medical device. It's tough to fit everything into a rollaboard and my laptop bag without having to leave my CPAP to its own carry case.