Columbia subject headings:
Air pilots--Certification--United States.
Air pilots--Retirement--United States.
Air pilots--Supply and demand--United States.
Local service airlines--United States.
Retirement, Mandatory--United States.
Harvard subject headings:
Air pilots--Certification--United States.
Air pilots--Retirement--United States.
Air pilots--Supply and demand--United States.
Local service airlines--United States.
Retirement, Mandatory--United States.
Princeton subject headings:
Air pilots--Certification--United States.
Air pilots--Retirement--United States.
Air pilots--Supply and demand--United States.
Local service airlines--United States.
Retirement, Mandatory--United States.