Columbia subject headings:
Aeronautics, Commercial--United States.
Air traffic control--United States--Finance.
National Airspace System (U.S.)--Finance.
United States. Federal Aviation Administration--Appropriations and expenditures.
Harvard subject headings:
Aeronautics, Commercial--United States
Air traffic control--United States--Finance.
National Airspace System (U.S.)--Finance.
United States. Federal Aviation Administration--Appropriations and expenditures.
Princeton subject headings:
Aeronautics, Commercial--United States.
Air traffic control--United States--Finance.
National Airspace System (U.S.)--Finance.
United States. Federal Aviation Administration--Appropriations and expenditures.