What Is a Codeshare Flight? Why Your Ticket Says One Airline and the Plane Says Another

A codeshare is an arrangement in which two airlines share a flight. One airline operates the aircraft. Both airlines sell tickets for it, and each one puts its own flight number, or "code", on it.

Every flight has two roles:

• The operating carrier is the airline that actually flies the aircraft. Its pilots, crew and plane are on the flight.
• The marketing carrier is the airline that sells the ticket under its own name and flight number. This may be the same as the operating carrier or a partner.

So when you buy a ticket from Airline A on a codeshare flight, the booking may say "Operated by Airline B". Your seat is real, and the aircraft is Airline B's.

Why do airlines do it?

Airlines do not fly everywhere. Building a global network on your own is very expensive, so airlines team up. A codeshare lets an airline:

• Offer more destinations without buying more aircraft or opening new routes.
• Fill seats on flights that would otherwise have empty ones, because two sales teams are selling the same flight.
• Offer smoother connections. A traveller can book one itinerary from a small city to a distant one across two airlines' networks.
• Build a relationship that can later grow into deeper cooperation.

For passengers, the benefit is more choice and often a single ticket for a journey that crosses two airlines.

Codeshare, interline and alliance: not the same

These terms are often mixed up:

• Codeshare: one airline sells seats on another's flight under its own flight number.
• Interline: two airlines agree to sell a single ticket covering flights on both, and to handle bags through, but each flight keeps its own airline's number. There is no shared flight code.
• Alliance: a wider group of airlines, such as Star Alliance, oneworld or SkyTeam, that cooperate on things like lounge access and loyalty benefits. Alliance members often codeshare with each other, but an alliance is not the same thing as a codeshare.
• Joint venture: a deeper arrangement where partners coordinate schedules and pricing on certain routes, which usually needs regulatory approval.

A codeshare is a lighter step than a joint venture. It is mostly about who sells the seat and under which number.

What to check when you book

Because two airlines are involved, a few practical details can differ from what you expect:

• Check "Operated by". On the booking and the boarding pass, the operating airline is named. That tells you whose aircraft, seat and cabin you will get.
• Baggage rules. The baggage allowance and fees usually follow the rules of the airline that sold you the ticket, or the rules for the whole itinerary, but it is worth checking, especially on multi-airline journeys.
• Check-in and airport terminal. You may need to check in with the operating airline, and it may use a different terminal from the airline you booked with.
• Frequent-flyer miles. Whether you earn miles, and with which programme, can depend on the fare type and the partners involved.
• Changes and problems. If your flight is cancelled or delayed, the airline that sold you the ticket is usually the first one to contact, though practice varies by airline.
• Seat and service. The seat, meals and entertainment are those of the operating airline, not the marketing airline.

Why you see the same flight listed several times

Codeshares can make a flight appear more than once in search results. The same aircraft may show up under several flight numbers, one from each partner that sells it. They are the same flight. Some booking sites combine them, and some do not.

Is a codeshare good or bad for passengers?

It depends. Codeshares can increase options and make journeys easier to book. But they can also make it harder to tell which airline you will really fly with, and prices can differ between the partners selling the same seat. Reading the "Operated by" line is the simplest way to avoid surprises.

The takeaway

A codeshare is one flight sold by two airlines. The airline whose name is on the booking may not be the one flying you. Next time you see "Operated by" on your itinerary, you will know exactly what it means.