# Codeshare Flight Delay: Which Airline Owes You?

> EU261 puts the €250–€600 on the operating carrier, not the airline whose code you booked. Article 2(b), the wet-lease rule, and when the first-leg carrier pays.

- Canonical: https://flightclaimletters.pages.dev/guides/codeshare-which-airline-pays/
- Section: Know your rights (https://flightclaimletters.pages.dev/guides/#reference)
- Published: 2 Sept 2026 · Updated: 6 Sept 2026 · Figures checked: 6 Sept 2026 · 5 min read
- Source site: flightclaimletters — https://flightclaimletters.pages.dev/ · General information, not legal advice.

Under EU261 the **operating carrier** — the airline that actually flew the aircraft — owes the €250, €400 or €600, not the airline whose code is on your ticket. Article 2(b) defines it. On a single booking, an EU carrier that flew the first leg can also owe for a later partner's leg.

## The rule: Article 2(b)

[Regulation (EC) No 261/2004](https://eur-lex.europa.eu/eli/reg/2004/261/oj/eng) puts every obligation on the "operating air carrier", defined in **Article 2(b)** as the carrier that performs or intends to perform a flight under a contract with a passenger. **Article 3(5)** confirms that where an operating carrier performs a flight for someone the passenger has no contract with, it is still the one on the hook.

- The **marketing carrier** is the airline whose flight code you booked. It is not who you claim from.
- The **operating carrier** is the airline that flew the aircraft. It owes the [Article 7 compensation](/guides/eu261-uk261-amounts/) and the [right to care](/guides/expense-reimbursement-letter/).

## How to identify it in 30 seconds

| Where to look | What it tells you |
|---|---|
| Booking confirmation or e-ticket | The "operated by …" line printed under the flight |
| Boarding pass | The operating airline's own flight number and logo |
| Flight-status site | Several codeshare numbers resolve to one operating flight |

If your ticket says "XX 6123, operated by YY", address the claim to YY.

This matters most inside an airline group, where the marketing and operating carriers often share owners but not obligations. [Lufthansa](/guides/lufthansa-compensation/), [Eurowings](/guides/eurowings-compensation/), [Swiss](/guides/swiss-compensation/) and [Austrian Airlines](/guides/austrian-airlines-compensation/) sit under Lufthansa Group; [Air France](/guides/air-france-compensation/), [KLM](/guides/klm-compensation/) and [Transavia](/guides/transavia-compensation/) under Air France–KLM; and [British Airways](/guides/british-airways-compensation/), [Iberia](/guides/iberia-compensation/), [Vueling](/guides/vueling-compensation/) and [Aer Lingus](/guides/aer-lingus-compensation/) under IAG. Check which one actually operated your flight before you write to the parent brand.

## Wet lease: the lessor is not the operating carrier

A wet lease supplies an aircraft **and** crew from another company. That looks as if it should shift liability to the lessor — the Court said no in *Wirth v Thomson Airways* ([C-532/17](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A62017CJ0532), 4 July 2018). A carrier that leases out aircraft with crew but does not bear operational responsibility is not the operating carrier, even where the booking confirmation names it as the operator. The operating carrier is the one that fixes the itinerary and offers the carriage.

So on a wet-leased flight you claim from the airline that sold and ran the flight, not the company whose crew was in the cockpit.

## The first-leg carrier can pay for a partner's leg

This is the rule most people miss, and it is worth real money on intercontinental trips. In *CS and Others v České aerolinie* ([C-502/18](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A62018CJ0502), 11 July 2019) passengers held a **single reservation** for connecting flights. The EU carrier operated the first leg on time; a later leg, flown by a non-EU partner **outside the EU**, arrived long delayed. The Court held that the Community carrier that operated the first leg remains liable for the compensation. It cannot point at the other operator and walk away.

That means an intercontinental journey booked as one ticket, starting in the EU, can be claimed against the EU airline you dealt with, even though the delay happened on a different continent on another airline's aircraft.

> **One booking reference is what carries the claim.** Two separately bought tickets are two journeys, and the *České aerolinie* rule does not bridge them. Check whether your legs share a single booking reference before you decide who to write to.

## If both airlines point at each other

1. Quote **Article 2(b)** and name the operating carrier from your own documents.
2. Attach the boarding pass or the "operated by" line as proof.
3. On one booking with a first leg flown by an EU carrier, add *České aerolinie* (C-502/18) and address the claim to that carrier.
4. If they still refuse, [escalate to the national enforcement body](/guides/escalate-to-regulator/) for the operating carrier's country or your country of departure.

## Does the frequent-flyer programme I booked through matter?

No. Liability follows the aircraft operator, not the alliance, the loyalty programme or the travel agent. A ticket issued on one airline's stock and flown by another is still the flying airline's claim.

## My flight was operated by a regional subsidiary. Who pays?

The subsidiary, if it operated the flight — a separate airline with its own certificate is its own operating carrier. That is why a claim addressed to the parent brand sometimes comes back rejected. Check the "operated by" line and send it there.

Which flights fall under the regulation at all is covered in [does EU261 cover non-EU airlines](/guides/eu261-non-eu-airlines/); whether the airline has a real defence is in [extraordinary circumstances](/guides/extraordinary-circumstances/).