Primary carrier

A primary carrier is the airline whose fare is selected and applied by a GDS to a specific portion of a passenger’s itinerary (called a fare component).

When a traveler searches for flights, the system compares fares from different carriers for each flight leg of the journey. Based on fare rules, routing, availability, and pricing, it selects the most appropriate fare. The airline whose fare is selected becomes the primary carrier for that part of the trip.

For example, a traveler books a flight from New York to Paris with a connection in London. Based on the best matches in terms of schedule and price, the GDS assigns British Airways as the primary carrier for the first leg of the trip and Air France for the second.