Montreal Convention: What International Air Law Says About Delays

Montreal Convention 1999 (MC99): The international treaty governing airline liability for delays, baggage loss, and personal injury on international flights. Ratified by 135+ countries including the US, UK, EU states, Canada, and Australia. Caps delay compensation at 4,694 SDRs per passenger (approximately $6,250 USD as of 2024).

The Montreal Convention 1999 is the primary legal framework for international air travel disputes. If your flight crossed an international border between two countries that have ratified the treaty, the Convention almost certainly governs your journey. Unlike EU261 or UK261, which provide fixed per-passenger payouts, the Montreal Convention requires proof of actual financial loss: you recover only what you can document, up to the treaty cap.

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  Applies to: International flights between two signatory countries.

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  Does not apply to: Domestic flights within a single country.

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  Delay liability: Article 19 creates a presumption of carrier liability for delay.

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  Compensation ceiling: Article 22(1) limits delay claims to 4,694 SDRs per passenger.

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  Statute of limitations: Article 35 requires claims within two years of actual or scheduled arrival.

For passengers departing from the United States on international flights, the Montreal Convention is typically the only applicable international treaty. The DOT's mandatory refund rules cover cancellations and significant changes, but they do not provide delay compensation payments. The Convention fills that gap by establishing airline liability and allowing passengers to recover provable financial losses caused by a delay.

On routes where regional frameworks such as EU261 or UK261 apply on the outbound leg from Europe, the Montreal Convention governs the inbound US-departure leg. Knowing which law covers which leg of your journey is the first step in identifying your rights.

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  US to Europe on a US carrier: Montreal Convention governs. No EU261 applies on the US-departure leg.

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  US to Europe on an EU carrier (Lufthansa, Air France, Aer Lingus): EU261 applies in both directions. See EU261 rights.

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  US to Canada: Montreal Convention governs. APPR may apply on the Canadian-departure return leg.

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  Between non-EU, non-UK countries: Montreal Convention is the primary international framework.

Article 19 states that the carrier is liable for damage occasioned by delay in the carriage by air of passengers, baggage, or cargo. The word 'damage' is key: the Convention compensates actual financial loss, not a fixed statutory fee. If a five-hour delay caused you no out-of-pocket expenses, you may have little to claim. If it caused you to miss a hotel deposit, purchase emergency accommodation, or lose a prepaid tour, those losses are recoverable.

Recoverable damages typically include meals and beverages purchased during the delay, hotel accommodation if an overnight stay was required, ground transportation caused by the delay, costs of rebooking on another carrier, non-refundable prepaid accommodation lost at the destination due to late arrival, and consequential economic losses where the causal link is clear and documented.

Key difference from EU261: EU261 pays fixed amounts (up to 600 EUR) regardless of your actual expenses. The Montreal Convention pays only proven losses up to the SDR cap. Keep every receipt: meals, taxis, hotels, and any prepaid bookings you forfeited.

Article 22(1) caps airline liability for passenger delay at 4,694 Special Drawing Rights (SDRs) per passenger. SDRs are an international monetary unit maintained by the International Monetary Fund (IMF). As of early 2024, one SDR equals approximately $1.33 USD, making the cap roughly $6,250 per passenger. ICAO reviews and updates this cap every five years.

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  SDR to USD: Approximately $1.33 per SDR as of 2024. Check the current rate at imf.org before filing.

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  Per passenger: Each passenger on the booking has a separate 4,694 SDR ceiling.

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  Proof required: The cap is a ceiling, not a guaranteed amount. You must document actual losses up to it.

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  Baggage is separate: Article 22(2) sets a distinct 1,288 SDR limit for baggage claims.

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  Cap lifted for willful misconduct: If the delay resulted from the carrier's own intentional or reckless act, the Article 22 cap does not apply.

Article 19 gives airlines a complete defense if they can prove that they and their agents took all necessary measures to avoid the damage, or that it was impossible for them to take such measures. Courts have interpreted this standard narrowly. Airlines cannot simply assert weather or air traffic control caused a delay: they must demonstrate that no reasonable operational step could have reduced the passenger's harm.

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  Severe weather: May support the defense, but only if the airline exhausted all mitigation options including rebooking.

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  ATC delays: Generally outside airline control, but the airline must show it mitigated the impact on passengers.

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  Technical faults: Routine maintenance failures typically do not support the defense, unlike the EU261 extraordinary circumstances standard.

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  Strikes: Depends on whether the strike was internal (airline staff) or external (ATC or airport workers).

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  Crew rest limits: If a delay cascades because crew hit legal rest requirements, courts may find the airline should have anticipated and prevented the situation.

A significant advantage of the Montreal Convention is flexible jurisdiction under Article 33. You can choose to sue in any of five locations, giving you the option to litigate where it is most affordable and accessible.

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  Carrier's country of domicile: Where the airline is legally incorporated.

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  Principal place of business: Often the airline's main hub country.

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  Where you bought the ticket: Can be your own country if you purchased online.

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  Place of destination: The country the flight was supposed to arrive in.

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  Fifth jurisdiction: Under Montreal Protocol 4, your own country of principal and permanent residence, if the carrier operates there.

For a US passenger who purchased a ticket through a European airline's US website to fly from New York to Paris, US courts are potentially available. This is a meaningful practical advantage for US-based claimants. For large claims near the SDR cap, consult an attorney about the most favorable forum.

Article 36 addresses journeys operated by multiple carriers. Each carrier is liable for delay on its own segment. However, if the first carrier's delay causes a cascading missed connection, the contracting carrier (the airline that issued the ticket) may bear broader responsibility under Article 19 for the full consequential delay.

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  Single ticket: The issuing carrier has overall contractual liability. A cascading delay caused by the first leg may result in the original carrier bearing full responsibility.

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  Separate tickets: Each leg is legally independent. Missing a connection booked on a separate ticket due to a first-leg delay is your risk.

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  Codeshare flights: The operating carrier (the one physically flying) is the primary party under Article 19. The marketing carrier may also have liability depending on the ticketing structure.

There is no centralized government portal for Montreal Convention delay claims. You file directly with the airline, and if that fails, through civil litigation. The process is more demanding than EU261 because you must document and prove every dollar of loss.

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   Write to the airline citing the Montreal Convention and providing your flight details, delay duration, and an itemized list of all losses caused by the delay.

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   Attach all receipts for meals, hotels, transportation, rebooking costs, and downstream losses such as missed prepaid hotel nights or forfeited tour deposits.

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   Request a formal written response within 30 days. Keep all correspondence.

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   If the airline denies or ignores your claim, file in small claims court (limits range from $2,500 to $25,000 by US state) or federal court for larger amounts.

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   Hire an attorney for claims approaching the SDR cap, particularly where willful misconduct may lift the cap entirely.

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  Boarding passes: All boarding passes for the delayed and any rebooked flights.

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  Flight status records: Screenshots from FlightAware or FlightRadar24 showing actual vs. scheduled arrival time.

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  Airline delay confirmation: Any email or text from the airline stating the delay and its stated reason.

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  Itemized receipts: Meals, hotel, taxi, and all other out-of-pocket costs during the delay.

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  Prepaid booking loss documentation: Hotel cancellation penalty receipts, tour deposit loss letters, or event ticket forfeitures.

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  Rebooking confirmation: If you were moved to a later flight, keep the revised itinerary.

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  Credit card statements: Backup evidence for any receipt that was lost.

Article 35 imposes a strict two-year limitation period. Claims must be filed within two years of the date the aircraft arrived, the date it ought to have arrived, or the date the carriage stopped. Courts consistently enforce this deadline. Ongoing negotiations with the airline do not pause the clock unless you have a written tolling agreement.

Do not wait: If you are negotiating with the airline and the two-year deadline approaches, file in court to preserve your rights. You can settle afterward. Missing the deadline forfeits your claim permanently.

On flights departing from EU or UK airports, both the Montreal Convention and regional passenger rights rules (EU261 or UK261) may apply simultaneously. Courts in Europe have generally held that EU261 fixed compensation and Montreal Convention actual-damage claims are independent entitlements. You can potentially pursue both, but cannot recover the same individual loss twice.

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  EU261 is usually better for delay compensation: Fixed amounts, no need to prove losses, 3-hour delay threshold.

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  Montreal Convention is better for large documented losses: If your actual financial loss exceeds the EU261 fixed amount, the Convention can cover the gap up to the SDR cap.

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  US-departure flights: Only the Montreal Convention applies as an international treaty. No EU261 or UK261.

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  Read the full guide to [US DOT passenger rights](/rights/us-dot) for what the DOT requires on US-originating flights.

The Montreal Convention replaced the Warsaw Convention of 1929. Warsaw set liability limits so low that they became meaningless as air travel expanded globally. Decades of patchwork amendments, the Hague Protocol, and inter-carrier voluntary agreements failed to modernize the system. ICAO negotiated the Montreal Convention in the late 1990s. It was adopted in Montreal in May 1999 and entered into force in November 2003. The Convention introduced dramatically higher liability caps, strict liability for personal injury under 100,000 SDRs, and the flexible five-jurisdiction litigation rule. The full treaty text is available through ICAO.

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  Not keeping receipts: Without documentation of actual losses, your claim has no evidentiary basis.

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  Confusing Montreal Convention with EU261: If you departed from the US, EU261 does not apply. Your claim is under the Convention.

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  Missing the two-year deadline: The limitation period is strict and cannot be extended by informal negotiations.

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  Accepting vouchers without reserving rights: Some airlines offer travel credits in settlement. Ensure accepting does not waive your Convention rights.

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  Not using the most favorable jurisdiction: Article 33 gives multiple forum options. Choose the fastest and cheapest.

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  Filing in court without first writing to the airline: Most courts expect documented prior attempts to resolve the dispute.

For help with your international flight claim, visit TravelStacks or read the complete guide to international passenger rights. If your flight departed from Europe, EU261 may give you fixed compensation without needing to prove individual losses.