The process of transferring passengers between two carriers flights, typically through a code sharing agreement. See Code sharing

The total number of passengers boarding aircraft . Includes both originating and connecting passengers.

a measurement representing one passenger transported one mile in revenue service.

A measure of unit operating revenue, reflecting the total passenger revenues received per seat, per mile. It is computed by dividing total revenues by available seat miles.

A measure of airline capacity; calculated as aircraft miles flown multiplied by the number of seats available for revenue passenger use.

The transport of passengers by a foreign carrier for purely domestic flights; illegal in all nations.

Nonscheduled service in which all seats are booked by a single entity such as a tour operator

An air carrier that is certificated to carry passengers for a fee.

An airline that operates short haul flights utilizing small capacity aircraft, typically turboprop planes.

Contracting certain tasks, such as maintenance, to an outside vendor as a means of reducing operating costs.

A bilateral aviation accord between two nations that widens access to markets and provides fare-setting freedom for air carriers.

An air carrier with annual operating revenues between $100 million and 1 billion dollars.

An air carrier whose annual operating revenues are greater than $1 billion dollars.

Revenue passenger miles as a percentage of available seat miles in revenue passenger service; measures the proportion of aircraft seating capacity that is actually sold and used.

An air carrier route structure providing broad geographic coverage of major sections of the U.S. without providing point-to-point service between every small airport.

An engine that creates propulsive thrust by expelling air at a much higher velocity than it has taken it in.

Distance between seats, or leg room

An air carrier with annual operating revenues of less than $100 million.

A rationed position in an airport's schedule for takeoff or landing. Only a handful of airports--those that are at designed capacity -- use a slot system.

The distance of a flight in miles. Stage length is frequently shorter than trip length, since two stages may be required to complete a flight.

A centralized database listing fare and flight data to book a flight.

A variety of aircraft designed to fly faster than the speed of sound. The Air France and British Airways Concorde are an example.

The passenger load factor that will result in operating revenues being equal to operating expenses, assuming constant revenue per passenger mile and expenses.

Aircraft utilization represents the average number of block hours operated per day per aircraft for the total fleet of aircraft.

Average fare represents the average one-way fare paid per flight segment by a revenue passenger.

Yield per passenger mile represents the average amount one passenger pays to fly one mile.

This represents the operating revenues divided by available seat miles.

This represents the operating expenses divided by available seat miles.

The practice of booking more passengers than available seats requiring some passengers to be bumped.

Bonus commission paid by airlines to travel agents for exceeding sales targets.