How we find cheap flight deals

The problem with searching yourself

Airline prices change constantly. The same seat on the same flight can cost very different amounts depending on when you look, because airlines release seats in price bands and adjust them as the plane fills up. A genuinely cheap fare might appear for a few hours on a Tuesday and be gone by the evening.

To catch those moments yourself you would need to search the same routes, from the same airports, across many different dates — every day. Most people don't have time for that, so they search once, book whatever they see and hope it was a fair price.

FlightLayer does the repetitive part for you. We check fares on the routes we track every day, keep a record of what each route usually costs, and only get in touch when something is clearly cheaper than normal.

Step 1: Tracking fares from UK airports

Every day, our system requests prices for a list of routes from UK airports — for example London, Manchester and Birmingham to Islamabad, Lahore, Dubai, Manila and Bangkok — across the months ahead. Looking across a wide range of dates matters, because the best deals are often on specific weeks rather than across a whole month.

The routes we track are shaped by where people actually want to go. Our route guides cover the destinations we focus on, including Islamabad, Lahore, Karachi, Dubai, Manila and Bangkok.

Step 2: Working out the normal price

A price on its own tells you very little. A fare that would be a bargain for a long-haul trip could be terrible for a short hop to Europe. So for each route we build up a picture of what it normally costs, based on the prices we have seen over recent weeks for similar travel dates.

This "normal price" also takes the season into account. Flights to Pakistan in the school summer holidays or to Manila just before Christmas are always going to cost more than in a quiet month, so we compare like with like rather than calling every off-peak fare a deal.

Step 3: Grading a fare

Once we know what a route normally costs, every new fare is compared against it. Small movements are ignored — prices go up and down by modest amounts all the time. We only pay attention when the drop is large enough to be worth changing your plans for.

We also flag fares that are the lowest we have seen on a route in a long time, even if the percentage drop is smaller, because those can be just as useful if you have been waiting to book a specific trip.

Step 4: Filtering out bad journeys

Cheap flights are sometimes cheap for a reason. Before a fare can become a deal, it has to pass a set of common-sense checks. The exact limits depend on the route — a sensible journey to Manila looks very different from a sensible journey to Dubai — but the principles are the same.

Step 5: Re-checking before sending

Flight prices can go up within hours. Before a deal goes into an email we check it again, and anything that has disappeared or risen back towards normal is dropped. This doesn't guarantee the fare will still be there when you click — the best deals can sell out quickly — but it cuts out most dead ends.

Step 6: The email you get

When you sign up, you tell us your home airport. Your weekly email then focuses on deals from that airport, with each one showing:

• The route and the price we found, and how far below normal it is
• The months or date ranges where the fare is available
• The airline, number of stops and a rough total journey time
• Anything important to check, such as whether checked bags are included
• A link to search or book the fare

Booking a deal

We don't sell tickets. When you click a deal, you go to the airline or a booking site to check the dates and pay. A few tips to make the most of a deal:

1. Act reasonably quickly — the best fares are often limited to a small number of seats.
2. Check the total price including bags and seat selection before you pay.
3. Check the connection time and whether the whole trip is on one ticket.
4. For very unusual fares, wait for your e-ticket before booking non-refundable hotels.
5. Check entry requirements on the GOV.UK foreign travel advice pages.

Our complete guide to finding cheap flights from the UK goes into much more detail on hidden costs, stopovers and your rights if things go wrong.

How we make money

FlightLayer is free. Some of the links on our site and in our emails are affiliate links: if you click through and search or book, the travel company may pay us a commission. This never changes the price you pay, and it doesn't decide which deals we send — a fare has to pass the same checks either way. You can read the details in our affiliate disclosure.