The guidelines below apply to most airlines, but it's important  to contact the airline directly by telephone to confirm details for any trip involving disabled passengers.

Here's a list of telephone numbers for major airlines: Airline Toll Free Phone Numbers

Wheelchairs

Every airline is required to have wheelchairs available. Most airlines have the narrow aisle wheelchairs for customers who require them to reach their seat.
Call  the airlines reservation number to obtain specific information and to order a wheelchair for points of departure, connection and destination. 

Hearing Impaired Passengers

Most Airlines have a special reservation service for those who have a hearing or speech impairment.  The phone links a telecommunications device (TDD) in the passenger's home or office with a similar machine in airlines reservation office. Passengers can conduct written communications with a specially-trained reservation agents 24 hours per day.

Special Diets

Most airlines offer special diets if given 24-hour advance notice. Diabetic, hypoglycemic, low cholesterol and low sodium are normally available.

Therapeutic Oxygen

Therapeutic oxygen is usually available for a service charge. Arrangements for therapeutic oxygen should be made by calling the airlines reservation number.