Revenue passenger-miles are a measure of the volume of air passenger transportation. Unused seat-miles (the difference between available seat-miles and revenue passenger miles) are used as a measure of airline capacity utilization. Another measure is the intensity of use of the equipment.
NOTE: A revenue passenger-mile is equal to one paying passenger carried one mile. Available seat-miles for an individual flight are the number of seats multiplied by the distance traveled. The data do not include international flights by U.S. domestic carriers or domestic flights by foreign carriers.
|Domestic Passenger Aviation||Oct-00||Oct-01|
|Available seat-miles (billions)||60.47||51.25|
|Available seat-miles percent change from same month previous year||3.48||-15.25|
|Revenue passenger-miles (billions)||41.52||33.06|
|Revenue passenger-miles percent change from same month previous year||3.03||-20.36|
|Unused seat-miles (billions)||18.96||18.19|
|Unused seat-miles percent change from same month previous year||4.47||-4.07|
NOTES: The current value is compared to the value from the same period in the previous year to account for seasonality. The data have been adjusted to have a standard 30-day month by multiplying the data for each month by the ratio: 30/(actual days in month).
These indicators are components of the passenger and overall aircraft load factors displayed in Aircraft Utilization-Passengers and Freight.
The dramatic changes in the September 2001 data reflect the impact of the terrorist attacks on September 11, 2001, on aviation, including several days in which commercial air operations were suspended.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, Air Carrier Traffic Statistics Monthly, October 2001.