codesharing

Reciprocal agreement through which two or more airlines offer their passengers one-booking, one-ticket, and (if there is no stopover) one check-in flight to a destination only one of them serves (with no loss of frequent-flier mileage). In this arrangement, the airlines share (for all legs of the flight) the same two-letter code that identifies the carrier in the Global Distribution System (GDS) used by travel agents.