Airlines are required to provide the assistance needed for people with disabilities. This ranges from help boarding the plane to assistive devices like crutches, hearing aids, or wheelchairs.
Airlines are required to pay for damages to mobility assistance devices (i.e. wheelchairs) although you must file a report directly after the flight or you risk not receiving proper pay or repairs.
Yes. Airlines must accommodate the needs of air travelers with disabilities. Due to the Air Carrier Access Act, airlines are prohibited from discriminating against a person based off of their disability. In addition to this, airlines are required to provide assistance (i.e. a wheelchair or other guided assistance to board, deplane, or connect to another flight; seating accommodation assistance that meets passengers' disability-related needs; and assistance with loading and stowing of assistive devices). When your powered wheelchair is stowed in the cargo compartment, the airline must return your assistive device to you in a timely manner as close as possible to the door of the aircraft, unless you ask to pick it up at baggage claim. If you feel you have been discriminated against based on disability, you can submit a complaint with the US Department of Transportation.