http://airconsumer.ost.dot.gov/publi...ngMobilityAids

Handling of Mobility Aids and Assistive Devices

To the extent consistent with various FAA safety regulations, passengers may bring on board and use ventilators and respirators, powered by non-spillable batteries. Assistive devices brought into the cabin by an individual with a disability shall not count toward a limit on carry-on items.

http://airconsumer.ost.dot.gov/publi...anceProcedures

EACH CARRIER MUST HAVE AT LEAST one Complaints Resolution Official (CRO) available at each airport during times of scheduled carrier operations. The CRO can be made available by telephone.

Any passenger having a complaint of alleged violations of the Air Carrier Access rules is entitled to communicate with a CRO, who has authority to resolve complaints on behalf of the carrier.

If a CRO receives a complaint before the action of carrier personnel has resulted in violation of the Air Carrier Access rules, the CRO must take or direct other carrier personnel to take action to ensure compliance with the rule. The CRO, however, does not have authority to countermand a safety-based decision made by the pilot-in-command of an aircraft.

If the CRO agrees with the passenger that a violation of the rule occurred, he must provide the passenger a written statement summarizing the facts and what steps if any, the carrier proposes to take in response to the violation.

If the CRO determines that no violation has occurred, he must provide the passenger a written statement summarizing the facts and reasons for the decision or conclusion.