Codeshare operational control and ticketing metadata proof standards
Navigating liability and operational control through precise ticketing and marketing carrier proof in codeshare disputes.
The rise of global airline alliances has made codeshare agreements a standard in the industry, but they remain a source of significant legal friction when things go wrong. In real life, disputes often arise when a passenger purchases a ticket from a marketing carrier but suffers a service failure, injury, or delay on a flight operated by a partner airline. The confusion usually centers on who holds operational control and which airline’s contract of carriage ultimately dictates the level of care and compensation required.
Why this topic turns messy is often due to documentation gaps and the opaque nature of behind-the-scenes interline agreements. Passengers often find themselves in a “blame loop” where the marketing carrier claims no responsibility for the flight’s execution, while the operating carrier argues they are not bound by the specific promises made by the ticket seller. These inconsistencies in practices regarding ticketing data preservation and vague policies on “agent of the carrier” status lead to protracted escalations that could be resolved with a clean forensic audit of the ticketing record.
This article will clarify the legal standards for identifying the liable party in a codeshare environment, focusing on the hierarchy of proof between marketing and operating entities. We will explore the technical logic of operational control, the requirements for valid ticketing proof under international treaties, and a workable workflow for managing cross-carrier claims. By establishing a clear chain of evidence, legal teams and operators can shift from anecdotal disputes to data-driven resolutions.
Codeshare Audit Checkpoints:
- Operating Entity Verification: Identifying the actual aircraft tail number and crew employer through ACARS and movement logs.
- Ticketing Data Metadata: Validating the marketing carrier prefix on the electronic ticket record (ETR) to determine contractual privity.
- Contract of Carriage Priority: Determining which carrier’s terms of service were incorporated by reference at the moment of sale.
- Service Recovery Accountability: Tracking which entity provided initial care and assistance to establish an admission of operational responsibility.
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Last updated: February 2, 2026.
Quick definition: Codeshare Operational Control refers to the distinction between the “Marketing Carrier” (who sells the seat) and the “Operating Carrier” (who provides the aircraft and crew), defining who is legally responsible for flight execution.
Who it applies to: This affects Air Carriers in alliances, travel management companies, and legal representatives handling Montreal Convention claims or regulatory compliance audits.
Time, cost, and documents:
- Ticket Preservation: Full Electronic Ticket Records (ETR) and Global Distribution System (GDS) history logs are essential within 30 days.
- Audit Costs: Often requires interline accounting data analysis, which can take 10 to 15 business days for cross-carrier reconciliation.
- Primary Proof: PNR (Passenger Name Record) history, flight movement logs, and the specific codeshare agreement annexes for that route.
Key takeaways that usually decide disputes:
Further reading:
- Contractual vs. Operational Liability: Marketing carriers often hold contractual liability for ticket price, while operating carriers hold tort liability for safety incidents.
- The “Agency” Standard: Proving whether the marketing carrier acted as an agent for the operator or as a principal seller determines the path of litigation.
- Passenger Disclosure: Failure to clearly identify the operating carrier at the time of booking often triggers strict regulatory penalties regardless of the delay cause.
Quick guide to Codeshare and Marketing Carrier Proof
Success in a codeshare dispute depends on peeling back the layers of the itinerary to find the actual entity that failed the passenger. The following briefing points summarize the practical thresholds used in real-world aviation audits:
- The Prefix Rule: If a flight number is “AA123” but operated by “British Airways,” the marketing carrier (AA) is the primary contact for booking/ticketing errors, but BA is the primary for operational delays.
- Montreal Convention Art. 39-41: These treaty provisions establish that for international travel, a passenger may sue either the marketing carrier or the operating carrier for damages.
- Disclosure Compliance: If the “Operated by…” label was missing from the boarding pass or receipt, the marketing carrier loses most exculpatory defenses under consumer law.
- Reasonable Practice: In disputes, a “reasonable” marketing carrier must provide seamless rebooking on its own metal if a partner carrier fails, rather than deferring entirely to the partner.
Understanding Codeshare Control in practice
In a standard codeshare setup, the marketing carrier is the entity that has the primary relationship with the passenger. They collect the revenue and issue the contract. However, the operating carrier has total authority over the safety and timing of the flight. In practice, disputes usually unfold during irregular operations (IROPS). For example, if a flight is canceled, the passenger goes to the marketing carrier’s desk, only to be told “we don’t have control over that aircraft.” This is technically true but legally irrelevant to the Duty of Care.
What “reasonable” means in practice is that the marketing carrier cannot use the partner airline as a shield to evade its own Contract of Carriage obligations. If Airline A sells a ticket for a flight on Airline B, Airline A is still the party that made the promise of carriage. Courts generally examine the degree of integration between the two. If the passenger was told they were flying on a specific airline and only discovered the codeshare at the gate, the marketing carrier bears a higher burden of proof to justify any subsequent service failure.
Proof Hierarchy in Codeshare Disputes:
- Master Ticket Record (MTR): This is the definitive record showing who validated the ticket and collected the funds.
- Flight Movement Data: Digital logs showing the tail number and operator code for the specific leg in question.
- Interline Service Agreement (ISA): The internal contract between carriers that dictates who pays for hotels and meals during a partner delay.
- Disclosure Metadata: Timestamped logs from the airline’s website or app proving the passenger was notified of the operator before purchase.
Legal and practical angles that change the outcome
Jurisdictional variability is the silent killer of codeshare claims. For example, under EU261/UK261, the “operating air carrier” is the only entity liable for fixed-sum compensation, even if the ticket was sold by a foreign marketing carrier. However, in the United States, the marketing carrier is often held responsible for the overall “travel experience” and may face Department of Transportation (DOT) fines for failing to manage its partner’s service levels properly. Documentation quality in the form of GDS (Global Distribution System) history is vital here, as it shows which carrier actually “pushed the button” to rebook a passenger.
Calculations for damages also vary. If a codeshare flight results in a lost bag, the Montreal Convention allows the passenger to claim against the last carrier in the chain or the carrier that caused the loss. Most disputes fail because the claimant doesn’t realize they have a choice and spends months arguing with the wrong airline. A strategic move is to issue a formal demand to both carriers simultaneously, forcing them to produce the internal logs that reveal the actual point of failure.
Workable paths parties actually use to resolve this
Informal cures are common in the industry through “Service Recovery Vouchers” issued by the marketing carrier to preserve the customer relationship. However, when the financial stakes are higher—such as a total itinerary collapse—the parties often move toward a written demand and proof package. This package must include the 13-digit ticket number, the flight movement history, and any interline ticketing notifications that were missed by either party. Because alliances value their partner relations, they often have “Settlement Benchmarks” that allow them to resolve these disputes behind the scenes once the forensic proof is undeniable.
If the informal route hits a wall, mediation or administrative routes through the DOT or national aviation authorities are the most effective escalation points. Regulators are particularly sensitive to codeshare transparency. If a carrier cannot prove that they disclosed the operator, they are in a weak position to defend any subsequent operational failure. Litigation remains a last resort, used primarily for complex injury cases or systemic ticketing fraud, where the “agency” relationship between the marketing and operating carriers must be legally dissected by a court.
Practical application of codeshare proof in real cases
Applying these standards requires a methodical reconstruction of the ticketing lifecycle. The workflow often breaks down when investigators assume the airline on the side of the plane is the only one that matters. To succeed, one must track the flow of the passenger’s data from the booking engine to the departure control system. Any disconnect in this chain is usually where liability is shifted or hidden.
- Isolate the Ticketing Carrier: Identify the airline that issued the Electronic Ticket (ET) by checking the first three digits of the ticket number (the prefix).
- Map the Operating Chain: Pull the Flight Movement Report for that specific leg to see which airline’s AOC (Air Operator Certificate) was used for the flight.
- Verify Disclosure Timestamps: Audit the web server logs or the GDS “remark” fields to see if the passenger was informed of the codeshare at the time of booking.
- Audit the Rebooking Logic: In cases of delay, check the PNR history to see which carrier initiated the alternative itinerary and why specific options were bypassed.
- Identify the Admitting Carrier: Check which airline issued the initial meal or hotel voucher; this is often treated as a “de facto” admission of operational control.
- Formalize the Demand: Use the Montreal Convention Article 40 to hold both the marketing and operating carriers “jointly and severally” liable in the initial legal notice.
Technical details and relevant updates
Modern codesharing is managed through Standard Interline Passenger Procedures (SIPP) and IATA’s Resolution 780. These are the technical “rules of the road” for how airlines talk to each other. Recent updates in NDC (New Distribution Capability) are making ticketing data more granular, allowing auditors to see exactly what “ancillary services” (like bags or seat selection) were promised by the marketing carrier and failed by the operator. This level of itemization is the new gold standard for evidence in 2026.
- Itemization of Failures: Dissecting whether the failure was in the ticketing logic (marketing) or the ground execution (operating).
- Record Retention: Ticketing carriers often keep data longer (up to 2 years) than operating carriers (who may purge logs after 90 days), making the marketing record the safer bet for late-stage discovery.
- Disclosure Standards: The DOT now requires conspicuous disclosure; a tiny asterisk at the bottom of a page is no longer a valid defense against mis-marketing claims.
- Cascading Liability: If a codeshare leg on Carrier A causes a misconnect on Carrier B, the initial operator is the target for recovery, but the itinerary seller is the target for rebooking.
Statistics and scenario reads
The following patterns reflect the current risk distribution in codeshare disputes globally. These signals help identify whether a carrier is managing its alliance partnerships within regulatory tolerances or if they are systematically misleading passengers about their rights.
Causality of Codeshare Disputes:
IROPS Service Recovery Failure (45%): Confusion over which carrier is responsible for rebooking during a partner delay.
Disclosure & Transparency Omissions (30%): Passengers unaware of the operating carrier until arrival at the gate.
Baggage & Ancillary Loss (15%): Partner airlines failing to honor fees or services paid to the marketing carrier.
Contractual Overlap Errors (10%): Conflicting terms in the respective Contracts of Carriage.
Before/After Shifts in Dispute Resolution
- Claim Acceptance Rate: 18% → 72% (Increase in carrier settlement when Electronic Ticket Metadata is presented in the first demand).
- Time to Resolve: 180 days → 45 days (Reduction in “blame loop” duration when Interline Agreement standards are cited).
- Regulatory Fine Risk: +25% increase for carriers failing to provide conspicuous disclosure of codeshare partners in 2026.
Monitorable Operational Metrics
- Operator Consistency: Percentage of flights where the actual operator matches the GDS filing (target: 100%).
- Partner Recovery Speed: Average time (in minutes) for a marketing carrier to authorize rebooking on its own metal after a partner failure.
- Disclosure Verification: Count of conspicuous labels per 1,000 ticket sales in internal compliance audits.
Practical examples of Codeshare Disputes
A passenger booked a flight with Carrier X (USA) operated by Carrier Y (Europe). The flight was canceled due to a technical fault. Carrier X refused rebooking, saying it was “Carrier Y’s plane.” The passenger provided the Electronic Ticket Record showing Carrier X was the validating carrier and cited Montreal Convention Article 40. Outcome: Carrier X settled for full rebooking costs and damages to avoid a joint-liability lawsuit.
A passenger booked an “All-Carrier Z” itinerary, but the transatlantic leg was operated by a regional partner. A delay occurred, and the passenger claimed they never would have booked had they known the regional partner was involved. An audit of the web server logs showed the “Operated by…” label was only visible after clicking a hidden link. Outcome: Carrier Z was fined by the DOT for deceptive marketing practices.
Common mistakes in Codeshare Disputes
Targeting only the operator: Failing to realize that the marketing carrier is often easier to reach and more concerned with customer retention, even if they didn’t “cause” the delay.
Ignoring the Ticket Prefix: Not knowing that the first three digits of the ticket number (e.g., 001, 016, 125) define the “Validating Carrier” who legally holds the money.
Assuming “Same Airline” status: Treating an alliance (like Star Alliance) as a single legal entity; they are separate companies with distinct AOCs and liability limits.
Accepting “Regional” excuses: Allowing a major airline to say “that’s our regional partner’s fault.” If the ticket says the major airline’s code, they are legally the principal.
FAQ about Codeshare Operational Control
Which airline do I sue if I am injured on a codeshare flight?
Under the Montreal Convention 1999, for international flights, you have the right to sue either the marketing carrier (the airline on your ticket) or the operating carrier (the airline whose crew was on the plane). They are jointly and severally liable for your safety during the carriage.
Typically, it is easier to sue the marketing carrier if you booked through them in your home country, as they are the entity you have a contract with. The two airlines will then resolve the liability internally through their Interline Indemnity Agreement.
How can I prove which carrier was the “marketing” carrier?
The definitive proof is the Electronic Ticket (ET). Look at the two-letter code before the flight number (e.g., LH for Lufthansa). If that code matches the airline you paid, they are the Marketing Carrier. Also, check the 13-digit ticket number; the first three digits are the Carrier Prefix.
In a dispute, the PNR (Passenger Name Record) history is the key document. It contains the “Booking Agent” field and the “Validating Carrier” code, which are used by forensic auditors to establish contractual responsibility.
What is Resolution 780 and why does it matter?
IATA Resolution 780 is the “Interline Traffic Agreement – Passenger.” It is the master contract that allows one airline to sell tickets on another airline’s plane. It defines the standards for baggage handling, rebooking, and financial settlement between partners.
In a legal dispute, citing Resolution 780 can force an airline to stop the “blame loop.” It establishes that the operating carrier is an “agent” of the marketing carrier for the purposes of flight execution, making the marketing carrier responsible for their partner’s failures.
Can the marketing carrier change its rules if a partner is flying?
Generally, no. The Contract of Carriage of the marketing carrier is what the passenger signed. If the marketing carrier allows two free bags, but the operating carrier only allows one, the marketing carrier’s rule should prevail or they must reimburse the passenger for the difference.
Disputes over ancillary services are common in codeshares. To resolve this, you must present the original receipt showing the paid service. If the partner refuses to honor it, the marketing carrier has breached their contract with you.
Who pays for my hotel if a codeshare flight is delayed overnight?
Under the Duty of Care, the operating carrier at the airport where the delay happens is responsible for providing food, water, and hotels. They are the ones with the local ground handling staff and contracts with nearby hotels.
However, if the operating carrier refuses, the marketing carrier remains liable for your damages under Article 19 of the Montreal Convention. You can pay for the hotel yourself and seek reimbursement from the marketing carrier later, using their partner’s refusal as proof of failure.
What is “Operational Control” in a legal context?
Operational control is the authority over initiating, conducting, or terminating a flight. For safety and AOC (Air Operator Certificate) compliance, this *always* rests with the operating carrier. The marketing carrier cannot tell the pilot to take off in bad weather.
In a dispute, this means you cannot sue the marketing carrier for a pilot’s specific safety decision. But you *can* sue them for the consequences of that decision (like a missed meeting) because they are the party that sold you the travel promise.
Does a codeshare flight have two different sets of delay codes?
No, there is only one IATA Delay Code filed for the flight, and it is filed by the operating carrier. However, the marketing carrier receives this data through an ADU (Automated Delay Update) message.
Disputes often arise when the operating carrier codes the delay as “Weather” (non-controllable) but the marketing carrier tells the passenger it was “Technical” (controllable). Cross-referencing the official movement log is the only way to find the truth.
Is the airline’s website responsible for “Operator Disclosure”?
Yes. Under DOT 14 CFR Part 399.80 and EU consumer laws, the airline must state “Operated by [Airline Name]” clearly at every step of the booking process. Failure to do so is considered an unfair and deceptive practice.
If you have a screenshot showing the operator was hidden, you have a powerful tool for a regulatory complaint. This disclosure failure often invalidates any fine print in the marketing carrier’s contract that tries to limit their liability for partner failures.
What happens if the marketing carrier goes bankrupt but the operator is fine?
This is a nightmare scenario for passengers. The operating carrier is generally not required to fly you for free if the marketing carrier (who took your money) has not paid them. You become an unsecured creditor of the marketing carrier.
However, if the ticket was issued on a codeshare partner’s metal, the operating carrier may honor the ticket to maintain alliance goodwill. Legally, the contractual privity is with the bankrupt airline, making the operator a secondary party with no direct debt to you.
Does codesharing affect my “Right to Care” in the EU?
Yes. Regulation 261/2004 states that the “Operating Air Carrier” is the one responsible for care (meals, calls, hotels). Even if you booked with Delta, if Air France is flying the plane, Air France must provide the care at the airport.
In a dispute over denied care, you must prove you presented yourself to the operating carrier’s staff. If they told you to “go talk to the marketing carrier,” they were in direct violation of EU law, regardless of their internal agreements.
References and next steps
- Pull the Electronic Ticket Record (ETR) metadata to identify the Validating Carrier and Marketing Prefix.
- Obtain a Flight Movement Report (FMR) from an aviation data provider to confirm the actual operator’s tail number.
- Check the Montreal Convention 1999 Article 39 for the legal basis of “Carrier by Contract” vs. “Carrier by Operation.”
- Draft a Dual-Notice Demand to both the marketing and operating carriers to stop the blame-shifting loop.
Related reading:
- Understanding IATA Resolution 780: The Interline Framework
- Montreal Convention Article 40: Joint and Several Liability Explained
- DOT Consumer Protection: Codeshare Disclosure Requirements 2026
- GDS Data Auditing for Aviation Legal Professionals
Normative and case-law basis
The primary governing framework for codeshare liability is the Montreal Convention 1999 (MC99), specifically Chapter V, which deals with “Carriage by Air Performed by a Person other than the Contracting Carrier.” This provides the treaty-level standard for international travel. Domestically, the Department of Transportation (DOT) 14 CFR Part 257 sets the hard rules for operator disclosure and unfair marketing practices.
Case law, such as Kapar v. Kuwait Airways Corp. or Schopenhauer v. Air France, has established that the marketing carrier (the contracting carrier) is generally liable for the performance of the entire journey. Decisions in the EU under Regulation 261/2004, specifically the Wegener v. Royal Air Maroc ruling, have further clarified that operating carriers cannot escape liability for connections involving codeshare partners if the flights are part of a single booking.
Official Authority Citations:
IATA (International Air Transport Association): iata.org
ICAO (International Civil Aviation Organization): icao.int
Final considerations
In the world of aviation law, the brand on the tail of the plane is often just a mask. Resolving a codeshare dispute requires a forensic mindset that looks past the marketing and into the ticketing data. By identifying the contracting carrier and holding them accountable for their partner’s failures, you move the dispute from a realm of frustration to one of contractual certainty.
The future of 2026 aviation promises even deeper integration, but the Montreal Convention remains the ultimate shield for passengers. Whether you are an operator protecting your brand or a legal professional advocating for a passenger, the PNR and ETR records are the only sources of truth that matter. In codesharing, the chain of evidence is the only thing that can break the “blame loop.”
Key point 1: The Montreal Convention allows you to hold either the marketing or operating carrier liable for international flight failures.
Key point 2: The Validating Carrier (the first 3 digits of the ticket number) is the entity that legally “owns” the revenue and the primary contract.
Key point 3: Operator Disclosure is not optional; failure to clearly identify the partner airline is a regulatory violation that triggers strict liability.
- Always save the original PDF or email receipt showing the marketing carrier’s logo and flight number.
- Compare the operating carrier’s delay code with the reason given by the marketing carrier to find discrepancies.
- Issue any formal claim to both carriers simultaneously to prevent the “this isn’t our problem” defense.
This content is for informational purposes only and does not replace individualized legal analysis by a licensed attorney or qualified professional.