14 CFR § 382.121 - What mobility aids and other assistive devices may passengers with a disability bring into the aircraft cabin?
(a) As a carrier, you must permit passengers with a disability to bring the following kinds of items into the aircraft cabin, provided that they can be stowed in designated priority storage areas or in overhead compartments or under seats, consistent with FAA, PHMSA, TSA, or applicable foreign government requirements concerning security, safety, and hazardous materials with respect to the stowage of carry-on items.
(1) Manual wheelchairs, including folding or collapsible wheelchairs;
(2) Other mobility aids, such as canes (including those used by persons with impaired vision), crutches, and walkers; and
(3) Other assistive devices for stowage or use within the cabin (e.g., prescription medications and any medical devices needed to administer them such as syringes or auto-injectors, vision-enhancing devices, and POCs, ventilators and respirators that use non-spillable batteries, as long as they comply with applicable safety, security and hazardous materials rules).