Cheapest day to book flights: what the data says

The old advice was to book on a Tuesday. The 2026 data says otherwise. Expedia’s annual Air Hacks report, which analyses millions of flight searches and bookings, found that Friday is now the cheapest day to book a flight, averaging around 3% less than booking on a Sunday. Sunday is consistently the most expensive day to buy.

That 3% matters less on a short European hop, but on a £600 return to New York it’s about £18 saved simply by waiting until Friday to click buy. On a family of four, it adds up.

That said, the day you book is a minor variable compared with two others: which day you choose to fly, and how far ahead you buy. Both of those have a much bigger impact on price. This guide covers all three, with the data to back it up.

The cheapest day to book a flight in 2026

Friday, based on the most current large-scale data available. Expedia’s 2026 Air Hacks report found that travellers who book on a Friday pay around 3% less than those who book on a Sunday. The worst day to buy is Sunday, followed by Monday and Saturday.

For context on why Tuesday used to hold this position: the old logic was that airlines would drop promotional fares on Monday evenings, competitors would match them by Tuesday morning, and there would be a brief window of cheap seats. That era is over. Ryanair, easyJet, and most major carriers now run fully dynamic pricing systems that update fares continuously, sometimes dozens of times per day, based on demand, remaining seat count, and competitor pricing. There is no consistent Tuesday dip to exploit anymore.

One practical caveat: these are statistical averages across millions of bookings. Your specific route and airline may not follow the pattern. If you find a good fare on a Sunday, buy it. Don’t wait for Friday and watch the price rise.

The cheapest day to fly (this matters more than when you book)

Booking day and departure day are two different variables, and most people conflate them. The data on departure days is actually clearer, and the savings are larger.

Flying on a Tuesday or Wednesday is consistently the cheapest option. Expedia’s 2026 data shows that Tuesday departures average around 14% cheaper than Sunday departures. Wednesday is similarly competitive. On a £200 return to Barcelona, that 14% is £28, and on a family of four the difference is meaningful.

The logic is straightforward: leisure travellers fly on Fridays and Sundays, and business travellers fly Monday morning and Thursday evening. That demand concentration pushes prices up on those days. Tuesday, Wednesday, and early Thursday have lower demand and consistently lower fares.

How far ahead you book — and why it matters most

Day of week is a single-digit percentage variable. Advance booking window can move prices by 30%, 50%, or more. This is where the real money is.

For Ryanair and easyJet, fares are lowest in two windows: immediately after seats go on sale (typically six months out), and again around six to eight weeks before departure. Between those windows, fares tend to drift upward as seats fill. The key question of whether budget airline prices drop as you approach the date is covered in detail in our guide on easyJet pricing closer to departure. The short answer: not reliably.

For full-service airlines — British Airways, Virgin Atlantic, Emirates — the pattern differs. Legacy carriers tend to hold fares more stable between promotional windows, with genuine deals appearing six to nine months out and occasionally again four to six weeks before departure. Last-minute on BA is almost always expensive.

As a general guide for UK travellers booking from now:

• European short-haul on budget airlines: book 6–8 weeks ahead for the best combination of price and seat choice
• European peak travel (bank holidays, July–August): book 3–4 months ahead regardless of airline
• Long-haul (USA, Caribbean, Asia): book 3–5 months ahead on full-service airlines
• School holiday travel: book as far ahead as possible; prices spike early and the booking window matters less than simply getting in before demand peaks

Budget airlines vs full-service: does the booking day matter equally?

Not quite. Ryanair, easyJet, and Wizz Air run genuinely dynamic pricing. Their algorithms update fares based on demand signals in near real-time. The “Friday is cheapest to book” finding applies at a statistical average across all airlines and all routes, but any individual Ryanair route on a Friday might be more expensive than the same route on Thursday. Budget carrier patterns are less predictable at the individual route level.

What Ryanair and easyJet do run are flash sales, typically announced midweek and running for 24 to 48 hours. If you’re watching for a sale rather than a specific route, Tuesday and Wednesday are worth monitoring. Both airlines push promotions at the start of the working week.

British Airways fares hold more stable. The midweek booking pattern is slightly more reliable with BA than with budget carriers, and Friday remains the strongest day to check and buy for long-haul fares.

Are last-minute flights ever genuinely cheaper?

Occasionally, on specific routes, when a budget airline has unsold seats to clear in the one to two weeks before departure. But it requires genuine flexibility: you need to be open on dates, departure airport, and destination. If you have school-age children, fixed annual leave, or a partner with different commitments, last-minute booking is not a viable strategy.

There is also a practical trap: the “cheap” last-minute fare often appears after you’ve already committed to accommodation, which eliminates most of the saving. The verdict on last-minute: it works for a minority of travellers with genuine flexibility. For everyone else, book when you’re ready, not when you’re hoping the price will fall.

Use price alerts rather than gaming the calendar

The most reliable approach is to set a price alert for your route and buy when the fare drops to a level you’re comfortable with, regardless of the day of the week it happens to be.

Google Flights is the most useful tool for UK travellers. Set your route, turn on price tracking, and Google emails you when the fare moves. The price graph also shows at a glance which dates in a given month are cheapest, useful if your departure date has some flexibility.

Skyscanner offers “watch this price” alerts and a whole-month view showing the cheapest fare for each day of the month, helpful if you can shift departure by a day or two.

One more variable worth considering: cabin bag only. Travelling without checked luggage removes a cost that often exceeds any savings from booking strategy. On Ryanair, a checked bag adds £30–£50 each way. Booking on a Friday saves you around 3%. Leaving the suitcase behind saves significantly more. Our guide to hand luggage sizes across all UK airlines covers what fits in the cabin on Ryanair, easyJet, British Airways, Jet2, and five other carriers.

The verdict

Book on a Friday where possible. Fly on a Tuesday or Wednesday if your dates are flexible. And spend the most time optimising your advance booking window: six to eight weeks for European budget routes, three to five months for long-haul.

Don’t over-engineer the calendar. The difference between booking on a Friday versus a Saturday is 1–2% on most routes. If a good fare appears on a Sunday evening, take it. The rule is a tiebreaker, not a rigid schedule to plan your life around.

The bigger wins come from flying midweek, booking well ahead of peak dates, and travelling cabin bag only wherever possible to avoid the checked luggage add-on costs that quietly inflate the price of a “cheap” flight.

Frequently asked questions

What is the cheapest day to book flights in the UK?
Friday, according to Expedia’s 2026 Air Hacks report. Bookings made on a Friday average around 3% less than bookings made on a Sunday, which is consistently the most expensive day.

What is the cheapest day to fly from the UK?
Tuesday and Wednesday are consistently the cheapest days to depart. Expedia’s 2026 data shows Tuesday departures average up to 14% cheaper than Sunday. Sunday is the most expensive day to fly in both directions.

Is Tuesday still the cheapest day to book flights?
No. Tuesday used to be cheapest because airlines released promotional fares on Monday evenings and competitors matched them by Tuesday morning. Modern dynamic pricing has removed that pattern. Tuesday is now roughly average as a booking day.

How far in advance should I book flights from the UK?
For European routes on budget carriers, 6–8 weeks ahead is typically the sweet spot. For long-haul on full-service airlines, 3–5 months. For peak summer and bank holiday travel, book as early as possible regardless of airline.

Are last-minute flights ever cheaper?
Occasionally, on specific routes where a budget airline has unsold seats to clear. But it requires genuine flexibility on dates and destination. For most UK travellers with fixed commitments, last-minute booking is not a reliable way to save money.

Does the cheapest booking day differ between Ryanair, easyJet, and British Airways?
Budget airlines use dynamic pricing that makes day-of-week patterns less predictable for individual routes. British Airways holds fares more stable, making midweek booking patterns slightly more reliable. For budget carrier flash sales, Tuesday and Wednesday are worth monitoring as that is when promotions tend to be announced.