What is a codeshare flight? Who flies it, who pays when it goes wrong

You booked Delta. The boarding pass says Air France. Your bag tag mentions KLM. When the flight lands four hours late, every airline involved points at another one. Nobody seems to own the problem, least of all the airline that took your money.

That's the strange world of codeshare flights. One seat can carry two or three flight numbers. The name on your booking often isn't the airline flying the plane. It matters more than it looks. Under EU and UK law, the airline that operates the flight usually owes you the €250 to €600, not the one that sold you the ticket.

At Gyro, we untangle codeshare bookings every day across more than 40 jurisdictions. Get the operating airline wrong and a valid claim can stall for months. Here is how codeshares work, how to read your booking and who pays when things go wrong.

What is a codeshare flight and how does it work?

A codeshare is a commercial deal between airlines. One airline operates a flight and lets one or more partners sell seats on it under their own two-letter code and flight number. The same aircraft might show up as AF 22, DL 8442 and KE 6402 on the departures board.

Airlines do it to stretch their networks without flying extra planes. A European carrier can sell you a seamless ticket to a small US city it has never flown to. Its American partner can do the same in reverse. You get one booking, one check-in and, usually, bags checked through to your final destination.

Think of it like a supermarket's own-brand cereal made by a big-name manufacturer. The box says one thing. The factory is somebody else's. The difference only matters when something goes wrong and you need to know who's responsible.

Most of the codeshare problems we see start at booking, long before the flight. Passengers book with the airline they know, never notice the "operated by" line and then send their claim to the wrong company. That first email often wastes weeks.

What is the difference between the marketing carrier and the operating carrier on a codeshare flight?

Every codeshare has two roles. The operating carrier flies the aircraft, employs the crew and runs the flight on the day. The marketing carrier sells the seat under its own flight number, and is often the airline that took your payment.

EC 261 defines the operating air carrier as the airline that performs, or intends to perform, the flight under a contract with you or on behalf of the person who has that contract. In plain terms, it's the airline in charge of the flight itself. The Court of Justice of the EU confirmed in Wirth v Thomson Airways (C-532/17) that the operating carrier is the one that decides to run the flight and takes operational responsibility for it.

US rules use slightly different labels. The DOT talks about the "transporting carrier" and the carrier whose code appears on your ticket. The idea is the same: one airline sells, another flies.

When a claim stalls, the reason is often a mix-up between these two roles. A marketing carrier can tell you, quite truthfully, that it didn't fly the plane. That doesn't end your claim. It just means the letter needs a different address.

How can you tell if your flight is a codeshare?

Look for the words "operated by". Both EU and US law require airlines and travel agents to tell you who actually flies your plane, before you pay and again if it changes.

In Europe, Regulation (EC) No 2111/2005 makes the seller name the operating carrier at booking, however you book. If that isn't known yet, you must be told the likely operator and then the real one once it's settled. If the operator changes later, the seller has to tell you straight away. You must then be told again at check-in or boarding.

US rules go further on presentation. Under 14 CFR 257.5, websites and apps have to show the operating airline next to each codeshare flight in the first search results. The name has to appear in text at least as large as the itinerary itself. A pop-up or roll-over doesn't count. Your purchase confirmation must also carry an "Operated by" notice for each affected flight.

Here's where to check:

• Your booking confirmation. Look for "operated by" next to each flight number.
• The search results page. The operating airline should appear beside the flight before you buy.
• Your boarding pass. It often shows both flight numbers, or the operating airline's name.
• The departures board. Shared flights usually rotate through every flight number they carry.

The detail we ask for first on every codeshare claim is the "operated by" line, copied exactly. Two airlines with similar names, or a regional partner flying under a big brand, can change which company has to pay.

Which airline do you claim EC 261 compensation from on a codeshare flight?

The operating carrier. Article 3(5) of EC 261 makes the airline that flies the plane responsible for meeting the regulation's duties. When it has no contract with you, it's treated as acting on behalf of the airline you booked with.

So if you booked a Lufthansa flight number that United operated from Frankfurt to Chicago, your claim goes to United. That can feel unfair if you never chose United. However, the law is built around the airline that controlled what happened on the day, from the crew roster to the technical checks.

The airlines then settle up between themselves. Article 13 of EC 261 lets an operating carrier that pays compensation seek redress from anyone else who caused the problem, including its codeshare partner. None of that is your concern. You claim once, from the right airline. They argue about the bill afterwards.

UK261 copies the same rule for flights covered by UK law. The UK Civil Aviation Authority also directs passengers to claim from the airline that operated the flight.

A marketing carrier will sometimes forward a claim to its partner without telling you. Meanwhile, the clock keeps running. Send your claim to the operating airline from the start. If you're unsure who that is, ask the marketing carrier to confirm it in writing.

Does EC 261 cover a codeshare flight into Europe operated by a non-EU airline?

No. This is the trap that catches the most codeshare passengers. EC 261 covers every flight departing an EU airport, whoever operates it. On flights arriving in the EU from outside, it only applies when an EU airline operates the plane.

That means the same seat, sold under the same flight number, can be worth €600 in one direction and nothing in the other. The airline whose code is on your ticket makes no difference. Only the operating carrier counts.

UK261 follows the same logic from Britain. It covers every flight departing a UK airport, and flights into the UK when a UK or EU airline operates them.

Source: Regulation (EC) No 261/2004, Article 3(1); UK261, Article 3(1). Flights within the US or between two non-EU countries can still fall under EC 261 when they form part of a single booking that started in the EU.

The table shows why passengers win or lose these claims before anyone looks at the reason for the delay. On a return trip from the US, check the operating carrier first. An Air France flight number flown by Delta into Paris leaves you with US rules only, while a Delta flight number flown by Air France keeps you inside EC 261.

We see this mix-up most on return legs from North America and the Middle East. Passengers assume the European airline on their booking brings European rules home with it. When the inbound plane belongs to the partner, it doesn't.

Who pays compensation when one leg of a codeshare connection is late?

On a single booking, the airline that operated a flight on your journey can be liable for the whole delay, even when its partner caused it. The Court of Justice made that clear in CS and Others v České aerolinie (C-502/18) in 2019.

Eleven passengers had booked one Czech Airlines ticket from Prague to Bangkok via Abu Dhabi. Czech Airlines flew the first leg on time. Etihad operated the second leg as a codeshare and landed 488 minutes late. The court held that Czech Airlines, as an EU airline that operated part of the booking, was in principle liable for the compensation. It could then recover the money from Etihad.

Two details shape these claims:

• The delay is measured at your final destination. What counts is how late you arrive at the end of the booking, not how late any single leg was.
• The distance is measured from start to finish. For a codeshare connection, compensation depends on the great-circle distance between your first departure airport and your final destination.

Separate tickets break all of this. If you booked the two flights independently, each is its own journey. A late first flight that makes you miss a connection on a separate ticket usually leaves you without a claim for the second.

Passengers connecting onto a non-European partner often assume the partner's delay puts them out of reach. When the booking started in the EU, or an EU airline flew one of the legs, that assumption can cost €600. The first thing we check on any codeshare connection is how the booking was built.

Which airline handles check-in, baggage and seats on a codeshare flight?

Mostly the operating carrier, with one important US exception. On the day, you travel under the rules of the airline flying the plane, from check-in deadlines and cabin bag sizes to meals and seat maps.

Here's how the practical side usually splits:

Source: 14 CFR 257.5 (US code-share disclosure); DOT baggage disclosure rules for itineraries to or from the US (2012); Montreal Convention, Articles 39 to 41 and 45; Regulation (EC) No 261/2004, Article 3(5). Seat and lounge rules come from each airline's own conditions and vary.

Baggage is where codeshares get messy. On trips to or from the US, the DOT expects the marketing carrier's bag allowance and fees to apply across the itinerary. That way, you shouldn't face a surprise fee when the partner's rules are stricter. Outside the US, airlines generally follow industry rules instead, which can point to the carrier flying the most significant part of your journey.

If a bag goes missing, the Montreal Convention gives you two airlines to choose from. It treats the airline you booked with as the contracting carrier for the whole trip and the airline that flew the leg as the actual carrier for its part. You can bring your claim against either, or both.

Report a lost or damaged bag at the airport before you leave, whichever logo is on the desk. The report protects your deadlines with both airlines. Arguing at the counter about whose bag it is just burns time.

Who refunds a cancelled codeshare flight under EU and US rules?

Legally, EC 261 places the refund duty on the operating carrier. In practice, the airline or agent that took your money usually processes it, because only the seller can reverse the original payment.

Under Article 8 of EC 261, a cancellation gives you the choice of a full refund or rerouting. The operating carrier is responsible for offering it. However, most operating carriers will send you back to the airline that issued your ticket, since that's where your fare sits.

In the US, the refund rules follow the money. Under 14 CFR 260.4, the airline that acted as merchant of record, meaning the one that charged your card, must provide the refund. If a partner operated the flight and failed to provide a paid extra, such as Wi-Fi or a seat, the operating carrier has to tell the seller so you get your money back.

Whichever system applies, you can insist on cash. Our guide to getting a refund on a cancelled flight covers how to turn down vouchers and what to do when an airline drags its feet.

The pattern we see most is ping-pong. The seller says the partner cancelled. The partner says the seller holds the ticket. Put your refund request in writing to the airline that charged you and copy the operating carrier. Then neither can claim they never heard about it.

Are airline alliances and codeshare agreements the same thing?

Not quite. An alliance is a broad partnership between many airlines covering lounges, loyalty points and connections. A codeshare is a specific agreement to sell seats on each other's flights.

Alliance members usually codeshare heavily with each other. Plenty of codeshares still cross alliance lines. Emirates, for example, belongs to no alliance yet sells seats on partner flights. The three global alliances look like this:

Source: Star Alliance and oneworld member pages, checked 29 October 2026; SkyTeam member list as published in October 2026. Philippine Airlines is listed by oneworld as a future member.

The European and American members matter most for compensation. A transatlantic codeshare operated by an EU or UK member is far more likely to fall under EC 261 or UK261 in both directions than one operated by its US partner.

When we sort a claim, alliance membership tells us very little on its own. It's the airline operating each leg that decides which law applies.

Is a wet-lease flight the same as a codeshare flight?

No, although they're easy to confuse. In a wet lease, one airline rents another airline's aircraft together with its crew. You might book Lufthansa and board a plane painted in another carrier's colours, flown by that carrier's pilots.

For EC 261, the question is who carries operational responsibility. In Wirth v Thomson Airways (C-532/17), passengers booked TUIfly from Hamburg to Cancún on an aircraft and crew leased from Thomson Airways. Their booking even said Thomson operated the flight. The Court of Justice still ruled that TUIfly was the operating carrier, because it decided to run the flight and set its route. Thomson had only supplied the plane and crew.

So the rule flips compared with a codeshare. On a wet-leased flight, the airline that sold the flight as its own service usually owes the compensation, whatever colours are painted on the tail.

Wet leases spike every summer, when European airlines rent extra planes to cover busy schedules. If the aircraft looks unfamiliar, keep your booking confirmation and boarding pass. They show which airline was running the flight. That's the one we claim from.

So is a codeshare flight good or bad news for your passenger rights?

Neither, as long as you know which airline is flying the plane. A codeshare doesn't take your rights away. It just moves them to a name that might not be the one you booked with.

The big rules are simple. Under EC 261 and UK261, the operating carrier owes the compensation. It also decides whether the law applies on flights into Europe or the UK. On a single booking, an EU airline that flew any leg can end up paying for its partner's delay. In the US, the airline that charged you handles the refund. Its bag rules usually travel with you, too.

Before you write off a delayed or cancelled codeshare flight, check two things: where that leg departed, and who operated it. If either points to Europe, you may still be owed up to €600 years after the flight. We check eligibility for free, identify the right airline and handle the claim from start to finish. Start a claim with Gyro. Or connect your inbox to Autopilot and we'll scan three years of flights, codeshares included, for money you didn't know you were owed.

Find out what your codeshare flight is worth

If your codeshare flight landed 3+ hours late or was cancelled at short notice, you may be owed €250 to €600 under EC 261 or £220 to £520 under UK261, or potentially more under the Montreal Convention. Gyro checks your eligibility for free. You keep 100% of whatever the airline pays.

• Free eligibility check in 60 seconds
• We identify the operating airline and send the claim to the right company
• Autopilot scans 3 years of flights in your inbox automatically

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