Airline Glossary

Aircraft utilization is the hours and minutes in a day an aircraft is used.

The ASM is one seat (empty or full) flown one mile. It's often referred to as the airlines industry’s measure of capacity.

The average length of haul is the average distance in miles a paying passenger is flown.

The average passenger fare is the average amount of passenger revenue per revenue passenger carried.

The average stage length is the average distance in miles the aircraft is flown per trip.

The CASM is the average cost of flying an aircraft seat (empty or full) one mile. It's often referred to as a “unit cost” measurement. The CASM is calculated as total operating expenses/total available seat miles.

Established by an act of Congress on October 15, 1966, the DOT consists of the Office of the Secretary and eleven individual operating administrations. Leadership of the DOT is provided by the Secretary of Transportation, who is the principal adviser to the President in all matters relating to federal transportation programs.

An enplaned passenger is one passenger, originating or connecting, boarded on an aircraft.

The load factor is the percentage of a plane filled with paying passengers. It's calculated as revenue passenger miles/available seat miles.

The passenger yield is the average amount of revenue received per paying passenger flown one mile. It's calculated as passenger revenues/revenue passenger miles.

The PRASM is the passenger revenue per seat (empty or full) flown one mile. It's often referred to as a “passenger unit revenue” measurement. The PRASM is calculated as passenger revenues/available seat miles.

The RASM is the total operating revenue per seat (empty or full) flown one mile. It's often referred to as a “unit revenue” measurement. The RASM is calculated as total operating revenues/available seat miles.

The revenue passengers carried is the number of Origination and Destination (O&D) paying passengers. The O&D is a measure of the point of origination of a passenger to the final destination.

The RPM is one paying passenger flown one mile. It's often referred to as the airline industry’s measure of “traffic”.

The trips flown is the number of one-way nonstop flights by all aircraft.