With a codeshare flight, the operating carrier is the airline that flies the plane, and the marketing carrier is the partner airline that sells seats on the operating carrier's flights. You can tell which carrier is operating your flight: Next to the flight number when you book the flight.

A codeshare flight is a business arrangement where two or more airlines "share" the same flight. One airline (the operating carrier) provides the actual aircraft, crew, and ground handling, while the other (the marketing carrier) sells seats on that flight under its own flight number and brand. For example, in 2026, you might book a ticket through United Airlines to Tokyo, but the plane you board is actually operated by ANA (All Nippon Airways). This allows airlines to offer a wider global network without the massive expense of flying their own planes to every destination. For the passenger, the main benefit is a seamless journey with single-ticket protection and synchronized baggage transfers. However, it is crucial to check the "Operated by" line on your confirmation, as the operating carrier's rules regarding baggage weight, check-in deadlines, and on-board amenities will almost always take precedence over the marketing carrier's policies.