Looking for cheap flights for your next getaway? Error fares could be your best bet.

As the name suggests, error fares are mistakes made when the price of a flight is listed online. Sometimes tickets are sold for far less than they should be, either due to human error or glitches in the complex systems that determine flight prices.

Savvy travellers can take advantage of these mistakes to secure a cheap holiday – but there are some risks with these low-cost fares.

Here’s everything you need to know about error fares, from how to find them to what could happen when you book them.

Cheap flight hack: How to find error fares

There are various websites and newsletters dedicated to finding cheap flights – including those that specialise in hacks like skiplagging and error fares.

Jack’s Flight Club is one example that delivers flight deals via an email newsletter and mobile app. Rather than offering tickets through its own platform, it redirects users to the airline or travel agency’s booking websites. Subscription is free, though Premium Membership offers access to more discounts.

The service provides alerts for cheap flights departing from all airports in Belgium, Denmark, Germany, Ireland, Luxembourg, the Netherlands, Norway, Sweden and the UK, as well as from Boston, Chicago, New York, Philadelphia and Washington DC in the US.

Secret Flying offers a similar service, with cheap flight deals and mistakes listed on its website and shared with subscribers via email. It searches for deals departing from airports worldwide and is free to use.

You can also set up price alerts for specific routes with aggregation services like Skyscanner or Google Flights.

Error fares are usually rectified or sell out quickly, so you’ll need to act fast to secure a cheap flight.

What are the causes of error fares?

Flight prices are often determined by complex algorithms that adjust them based on data like demand for particular routes or distance.

They may be adjusted further by online travel agencies selling flights as a third party. Sometimes error fares occur when these agents list prices that differ from the airline’s direct pricing – either due to human error or a glitch in the system.

In other cases, conversions from one currency to another may be listed incorrectly, making the flight far cheaper than it should be. The airline may also miscalculate the mileage of connecting flights, resulting in lower taxes.

Airlines sometimes make the mistake of listing a premium, business or first class flight at an economy rate too. This is often where you can make the biggest saving, as economy fares are largely made up of taxes and surcharges which usually remain the same regardless of errors.

As technology improves and AI takes over, error fares are likely to become less common and be rectified faster when they do occur.

What are the risks of booking an error fare?

Error fare tickets are usually honoured by airlines – but this is not guaranteed unless your country has laws to enforce it.

These usually take into account whether the error was obvious enough for the consumer to notice it, how long it was left online, and how quickly the buyer was notified of it.

But passengers taking advantage of these cheap fares should bear in mind that the airline can cancel your flight if it realises the error and decides not to uphold it. In such cases, you are entitled to a full refund. You will not be billed the full price of the ticket without your permission.

For this reason, sites like Jack’s Flight Club and Secret Flying advise against making other travel plans like booking hotels or accommodation until the last minute.

Secret Flying says there is a “small chance” the airline may cancel the ticket. Therefore it is best to book refundable or flexible accommodation if you are planning to fly on an error fare.

If you accidentally book an error flight because the discount was not enough to be deemed abnormal, however, you may be entitled to contest the fare if the airline cancels your flight, or gain compensation from the airline for any extra costs incurred such as hotel bookings.

Jack’s Flight Club says that around 70 per cent of the error fares it lists are honoured by airlines, as they tend to avoid the hassle and bad publicity of cancelling tickets. Once your ticket has been issued, it is less likely to be cancelled.

For the best chance of having your error fare honoured, book directly with the airline and only book tickets listed at plausible discounts.

How much could you save with error fares?

Recent error fares shared by Jack’s Flight Club include a €46 flight from London to Los Angeles with Norwegian; Amsterdam to Peru for €164 with AeroMexico; and Paris to Tokyo for €290 with Aeroflot over the busy Christmas period.

These journeys would usually cost around €410, €800 and €900, respectively.

Secret Flying recently listed business class flights from several German cities to Cusco, Peru from €834 for a round trip with Iberia and LATAM Airlines. Business class flights from Munich typically cost upwards of €3,000.

The site also recently alerted readers to €250 flights from Stockholm, Sweden to Johannesburg, South Africa with Swiss International Air Lines – around half the usual price.