Mistake Fares: What They Are, How to Find Them, and Whether They'll Be Honored
May 3, 2026
In 2012, United Airlines briefly sold business class tickets from the US to Hong Kong for $43 return — a "mistake fare" caused by a currency conversion error that left taxes and fees in New Zealand dollars rather than US dollars. Thousands of people booked before the fare was pulled. United honored almost all of them. The passengers flew business class to Hong Kong for $43.
Mistake fares are real. They're not mythological. They happen regularly enough that communities of fare watchers have built entire websites around finding them. Understanding what they are, why they occur, and what your rights look like if one gets canceled is genuinely useful knowledge for anyone who flies frequently.
What Is a Mistake Fare?
A mistake fare is a flight ticket priced significantly below its intended price due to a human or technical error during the fare-loading process. Airlines and OTAs load enormous numbers of fare rules into their systems at any given time, and the process is complex enough that errors occur regularly. Common causes:
Currency conversion errors (the most dramatic, like the United HKG example). A fare entered in one currency gets converted incorrectly, producing a price that's a fraction of intended.
Missing fuel surcharge. Fuel surcharges are typically loaded separately from base fares. When the surcharge layer fails to attach, you get a ticket priced only on the base tariff — which can be extremely low.
Transposition errors. A human data entry error turns £1,200 into £120 or €890 into €89. These can persist for hours before being caught.
OTA glitches. Sometimes the error isn't at the airline level at all — it's a third-party booking platform that has miscalculated or misapplied a promotional discount, creating a sub-floor price that the airline never authorized.
How Long Do They Last?
Most mistake fares survive for minutes to hours before being caught and corrected. The window depends on how much traffic the route normally receives and how quickly the airline's revenue management team monitors outlier bookings. A domestic US route with high booking volume might trigger an alert within 20 minutes. A niche international route with low booking frequency might persist for several hours.
This is why communities that track mistake fares maintain alert systems: you need to act within minutes or the window closes.
Where to Find Them
The most reliable mistake fare sources are community-driven:
Secret Flying (secretflying.com) is the most comprehensive aggregator of reported mistake fares globally. It lists current and recent confirmed mistake fares with booking links and notes on validity.
Scott's Cheap Flights (now Going.com) covers US-based mistake fares and genuine error fares with a paid tier that alerts faster.
Reddit's r/flightdeals and r/churning communities often surface mistake fares before aggregator sites, because individual members are watching specific routes or airlines.
Airline direct sites occasionally produce their own errors that don't appear on OTAs — particularly when fare rule updates fail to propagate correctly. This is why it's worth checking directly if you hear about a suspected error.
Will the Airline Honor the Fare?
This is the most important question, and the answer varies significantly by jurisdiction and airline.
In the United States, the Department of Transportation (DOT) rules are relatively consumer-friendly: airlines are generally expected to honor tickets that have been purchased and confirmed. DOT guidance has historically leaned toward enforcement of mistaken fares, particularly if the airline has already issued a booking confirmation. Airlines can petition for an exception if the error is "obvious" — but the threshold for what qualifies as obvious is contested.
In the UK and EU, the situation is more nuanced. The Civil Aviation Authority (CAA) doesn't have an explicit rule requiring honor of mistake fares. However, consumer contract law applies: once a booking confirmation is issued, a contract has been formed, and canceling it may require compensation (a refund plus potentially additional damages). Several UK cases have resulted in airlines honoring mistake fares rather than facing consumer law challenge.
Australian consumer law provides some of the strongest mistake fare protections globally — airlines have been required to honor clearly mistakenly priced tickets that were already confirmed.
Practically: if you book a mistake fare and the airline tries to cancel it, file a complaint immediately with your jurisdiction's aviation regulator. Keep all confirmation emails. Don't contact the airline proactively before flying.
How to Book a Mistake Fare
When a mistake fare appears:
1. Book directly with the airline if possible, not through an OTA. Airline direct bookings produce contracts directly with the carrier, which is cleaner for enforcement purposes.
2. Book on a credit card, not debit. If the airline cancels and refuses to refund, your credit card company may provide chargeback protection.
3. Don't plan beyond the booking until the fare has been booked for 24 hours without cancellation notice. Don't book non-refundable hotels.
4. Check for the "24-hour free cancellation" rule: in the US, airlines are required to allow free cancellation within 24 hours of booking. If you're uncertain whether the fare is real or mistaken, you can book and cancel within 24 hours with no financial exposure.
The Difference Between a Mistake Fare and Just a Cheap Fare
Not all very cheap fares are mistakes. Airlines run genuine sale fares, flash sales, and seat-fill discounts that look remarkably similar to mistake pricing. The tells that suggest an actual error rather than an authorized sale:
The fare appears on the airline's own website but not in any official promotional communication. Genuine sales are marketed; mistake fares aren't.
The route has no historical precedent for the price point. If a business class ticket from London to Tokyo has never been below £1,200 and is suddenly showing at £180, that's a signal.
The fare disappeared within hours. Authorized sales are typically live for days.
Where to Find Them: Secret Flying, Fly4Free, and the Alert Ecosystem
The mistake fare ecosystem runs on a handful of reliable communities and alert services. None of them guarantee you'll catch every error, but together they dramatically increase the odds.
Secret Flying (secretflying.com) is the closest thing to a global mistake fare registry. The site is community-driven and updated around the clock by contributors who monitor airline and OTA booking platforms. It lists current and recently confirmed mistake fares with booking instructions, notes on whether airlines have begun cancelling, and an archive of past fares for context. Coverage spans dozens of origin countries and is consistently more international in scope than US-centric alternatives.
Fly4Free (fly4free.com) runs a similar model with strong European coverage, particularly for fares originating in Poland, the UK, Germany, and the Nordics. The site differentiates between genuine error fares and authorized sales, with editorial commentary on which fares are likely to be honored and which look shaky. Fly4Free also maintains an email alert list for subscribers by origin country.
Going.com (formerly Scott's Cheap Flights) covers the US market specifically. The free tier delivers alerts with some delay; the paid tier (around $49/year) delivers alerts faster and covers more routes. For travelers based in the US who want the fastest notification on US-origin fares, this is the most reliable paid option.
Reddit communities surface fares quickly: r/flightdeals is a high-volume feed of cheap fares, not all of which are mistakes, but the community labels confirmed errors clearly. r/churning has a more travel-hacker-oriented audience and often discusses mistake fares in the context of points redemption and credit card strategy.
X (formerly Twitter) accounts like @theflightdeal and @SecretFlying push alerts in real time. During active mistake fare windows, these accounts post within minutes of a fare appearing.
The practical workflow: set up alerts from two or three sources, and keep a booking method ready to execute quickly. A saved credit card, a passport available, and a sense of which travel windows you'd be free to fly — these things allow you to book in under three minutes when a good fare appears.
Success Rate and What to Expect
The uncomfortable truth about mistake fares: the success rate — the proportion of booked mistake fares that result in an actual flight — is not 100%, and varies significantly by airline, jurisdiction, and error type.
Airlines that have historically honored mistake fares reliably include United Airlines, British Airways, Delta, and Lufthansa. These carriers have built institutional processes for handling mistake fare situations, and where the error is attributable to the airline's own systems, they tend to honor rather than face regulatory and reputational costs. US carriers are particularly likely to honor because DOT guidance makes cancellation more legally complicated.
Airlines more willing to cancel and refund include some budget carriers and certain Asian carriers, where the legal framework is less prescriptive about enforcement. In these cases, booking immediately and filing a complaint with the relevant aviation authority if canceled is the right approach.
The error type matters. Currency conversion errors (like the United HKG $43 case) produce fares so clearly wrong that airlines know cancellation would be contested. Missing fuel surcharge errors are more ambiguous. Transposition errors (£120 instead of £1,200) sit in between: clearly mistaken in absolute terms, but the airline must demonstrate the error was obvious under regulatory frameworks.
Experienced mistake fare hunters estimate that roughly 70-80% of fares booked on airlines with good track records end up being honored. The remainder get canceled with a full refund. Since you haven't lost money on the refunded ones — provided you book on refundable methods and don't book non-refundable hotels until 48 hours pass — the downside of an unhonored booking is time spent, not money lost.
Recent Examples
Mistake fares continue to appear regularly. A few documented examples from the past 12 months illustrate the range:
Finnair business class from Europe to Asia at $400-500 return (normal price $2,000-3,000). A fare-loading error on routes via Helsinki produced confirmed bookings for several hundred passengers. Finnair honored the majority; those canceled received standard refunds.
Air India economy fares from the US to India at $180-220 return — roughly 80% below normal pricing — appeared briefly on multiple US-based OTAs simultaneously. Air India canceled a portion of bookings but honored several hundred that had already received full confirmation and ticket numbers.
LOT Polish Airlines published Warsaw to Tokyo via Seoul fares at €290 return (business class) for approximately 40 minutes before correction. The error originated from a missing segment charge on one leg. LOT honored all bookings that had received confirmation emails.
Mistake fares are not predictable in route or airline. What is predictable is that they continue to appear at roughly the same frequency — several confirmed examples per month globally — and that the communities tracking them have become more efficient at surfacing them quickly.
The EU261 Angle
EU Regulation 261/2004 is the primary passenger rights framework covering flights departing from EU airports (and flights arriving in the EU on EU-registered carriers). It is primarily known for covering delays and cancellations — but it has direct relevance to mistake fares.
If you hold a confirmed booking on a flight that the airline subsequently cancels — including cancelling because they have decided not to honor a mistake fare — EU261 may entitle you to compensation of €250–600 depending on flight distance, in addition to a full refund. The airline's argument that the fare was a mistake is not explicitly listed as an exemption from EU261 obligations in the regulation's text. Several passengers have successfully claimed EU261 compensation on top of refunds when airlines cancelled mistake fare bookings on EU routes.
The caveat: EU261 is not universally enforced without effort. Airlines contest these claims, and pursuing them through a national enforcement body or the courts takes time. But for business class mistake fares where the compensation ceiling is €600 per passenger, the calculation makes sense. Services like AirHelp, ClaimCompass, and Compensair handle EU261 claims on a commission basis (typically 25-35% of the award) for travelers who prefer not to navigate the process themselves.
Non-EU travelers on EU-departing flights are equally covered by EU261. If you fly from Paris to anywhere on Air France and the booking gets canceled, you have the same EU261 rights as a French citizen.
RegionFare and Systematic Price Monitoring
Regional price differences across booking markets can look like mistake fares but are often legitimate. A flight that costs £340 in the UK market and £265 in the Israeli or South African market isn't a mistake — it's the airline applying regional pricing strategy, as covered in other articles here. RegionFare surfaces these systematically, which means you see prices that are genuinely low without the enforcement uncertainty of a mistake fare.