For future reference, here is what I found on the aa.com website:

1.http://www.aa.com/i18n/travelInforma...false&from=Nav
Additional items that will be allowed above and beyond the restrictions listed above include:Assistive devices for passengers such as wheelchairs, walkers and CPAP machines

2.http://www.aa.com/i18n/travelInforma...AndDevices.jsp
Carry-On Assistive Devices
Canes, walkers, CPAP machines and other assistive devices capable of being collapsed small enough to fit into approved overhead and under seat stowage areas are welcome and do not count toward your carry-on item limit.

Assistance stowing carry-on baggage that meets baggage limits is available for customers with disabilities who request extra assistance. Due to storage limitations, some equipment or devices may have to be checked as baggage if it is not required during flight. All assistive devices must be packed separately from normal baggage to avoid baggage charges.

3. http://www.aa.com/pubcontent/jbax/in...thmedinfo.html
CPAP machine
*Medical clearance is not required for the carriage or use of CPAP machines (used in the treatment of sleep apnea) as fitness to travel will not be in doubt.
*CPAP machines can be plugged into a laptop power-point, where available, with a suitable adaptor.
*Maximum power output from the laptop points is 75 Watts and, if your equipment draws more than this, the outlet will be automatically deactivated.
*We cannot guarantee that any of the laptop points will be serviceable. If you intend to use one in flight, we recommend that you use a dry-cell battery-operated device.

Two points:

1. What is interesting for #3 is that it's British Airways content but on the aa.com website. According to AA customer service, this therefore applies only to BA and not AA.

2. Customer service says best thing to do is when booking, notify them ahead of time re cpap to avoid the problems posted here. And of course, print out the two pages cited above to wave in front of those 'smart ticket agents/supervisors, et al'

Slightly OT but here is Cathay Pacific's website re same topic (I mention only because they are also partners with AA):

http://www.cathaypacific.com/cpa/en_...0011d21c39____
# For Ventilator, respirator, CPAP machine and POC (Portable Oxygen Concentrator) we require advance notice up to 48 hours before the scheduled departure time of your intended flight.
# For any device without a manufacturer label stating that it complies with applicable FAA requirements for portable electronic medical devices, up to 2 weeks advance notice may be required. (Note: Only FAA approved devices will be accepted for flights to or from the US)