Columbia subject headings:
Aeronautics--Economic aspects--United States--Forecasting.
Aeronautics--United States--Forecasting.
Airlines--Technological innovations--United States--Forecasting.
Harvard subject headings:
Aeronautics--Economic aspects--United States--Forecasting.
Aeronautics--United States--Forecasting.
Airlines--Technological innovations--United States--Forecasting.
Princeton subject headings: