WILL YIELDS DECLINE IN THE FUTURE? : LESSONS FROM THE PAST
CHART 1. US DOMESTIC SYSTEM REAL YIELDS SINCE 1950. -- CHART 2. COMPARISON OF REAL YIELDS SINCE 1950. -- CHART 3. US AIR SYSTEM AVAILABLE SEAT MILES PER GALLON SINCE 1950. -- CHART 4. AIRLINE EMPL- OYEE PRODUCTIVITY VS NON-FARM EMPLOYEE PRODUCTIVITY IN US. -- CHART 5. US AIRLINE REAL UNIT LABOUR COSTS SINCE 1957 CHART 6. AVERAGE SEATS PER DEPARTURE AND PASSENGER TRIP LENGTH IN WORLD SINCE 1955. -- CHART 7. WORLD AIRLINE OPERATING PROFITS SINCE 1955. -- CHART 8. AIRLINE EMPLOYEE PRODUCTIVITY IN US VS IATA