Search for advice on when to book flights and you will find precise-sounding answers: a set number of weeks ahead, a particular day of the week, a time of night. The truth is less tidy. Fares are set flight by flight, by systems that respond to demand, so no single rule works for every route. What does work is understanding how prices tend to move, knowing which dates sell out first and watching your route for long enough to recognise a good fare when you see one.
How airline pricing works, in brief
Each flight has a limited number of seats at each price level. The cheapest levels usually sell first, and when they are gone the price steps up to the next one. Airlines adjust how many seats they release at each level depending on how bookings are going, which is why a fare can jump overnight and occasionally fall again. Sales and promotions release extra seats at lower prices for a short time.
Two consequences follow. On busy dates, waiting usually means paying more, because other people buy the cheaper seats first. On quiet dates, there may be no rush, and a fare can stay steady for weeks.
Rules of thumb by type of trip
These are general patterns, not guarantees. Use them to decide how closely to watch prices, not as fixed deadlines.
Short-haul in Europe, outside the holidays
Routes such as London to Barcelona, London to Rome and London to Lisbon have several airlines and many flights a day, so there is usually plenty of choice for off-peak travel. Booking a month or two ahead is generally comfortable, and watching for sales can pay off. Last-minute bargains on popular Friday and Sunday flights are rare, though, as those seats sell to people with no choice of date.
School holidays, half-terms and bank holidays
If you are tied to school dates, book as early as you can commit. Fares for half-term, Easter and the summer holidays tend to climb as the dates approach, because demand is fixed and the cheaper seats sell first. School holiday dates also vary across the UK. Scottish schools usually break up for summer in late June and go back in mid-August, earlier than schools in England and Wales, and half-term dates can differ between local authorities. If your dates fall outside the main rush, you may find better fares on family routes such as Manchester to Málaga.
Long-haul
Long-haul routes often have fewer competing airlines and fewer flights, so the cheapest seats can go earlier. For Christmas, New Year, Easter and the summer holidays, it is sensible to book several months ahead on routes such as London to New York, London to Dubai or London to Bangkok. For off-peak travel, start watching early and book when you see a fare you are happy with.
Major events
Big sporting events, festivals and trade fairs push up both flights and hotels. If your trip is built around a fixed event, book flights and accommodation as soon as the dates are confirmed, choosing a free-cancellation hotel rate if your plans are not certain.
The cheapest day to book is mostly a myth
You will often hear that booking on a particular weekday is cheaper. Any effect is small and inconsistent compared with the effect of the day you actually fly. Flights on Tuesdays, Wednesdays and Saturdays are often cheaper than those on Fridays and Sundays, and very early or late departures are often cheaper than mid-morning ones. Being flexible by even a day or two either side of your ideal dates usually makes more difference than when you press the button.
Use flexible-date searches and fare alerts
- Search a range of dates. Look at a week or a whole month to see where the cheaper days fall.
- Set alerts. Set a fare alert for your exact route and, if you can, for a nearby alternative airport. Alerts show you how fares move without you checking every day.
- Decide on a target in advance. After a few weeks of watching you will know what a reasonable fare looks like for your dates. When one appears, book it rather than holding out for a perfect low.
- Compare the total. Add bags, seat selection and any payment charges before comparing airlines. A low-cost fare with a checked bag can cost as much as a full-service ticket.
Widen the search
- Alternative airports. London has six main airports: Heathrow, Gatwick, Stansted, Luton, London City and Southend. In New York, compare JFK, Newark and LaGuardia, for example on New York to Miami. Include the cost and time of getting to each airport.
- Open-jaw tickets. Flying into one city and home from another, such as into Rome and out of Naples, saves backtracking and can sometimes save money.
- Two one-way tickets. On short-haul routes, combining one-way fares on different airlines can beat a return with a single airline.
- One stop instead of nonstop. On long-haul routes, one-stop itineraries are often cheaper, at the cost of a longer journey.
Booking safely when prices move
- Check that the names on the booking exactly match the passports.
- Read the fare rules before you pay. Cheaper fares often allow no changes, or charge a fee plus any fare difference.
- For flights to or from the US booked directly with an airline at least a week before departure, US rules generally let you either hold the fare or cancel without penalty within 24 hours of booking. Check the airline’s own policy.
- If you buy separate tickets for connecting flights, a delay on the first is not the second airline’s responsibility, so leave generous connection times.
- Buy travel insurance when you book, not just before you leave, so you are covered if something happens in between.
A worked example
Consider two trips on the same route. A family tied to the October half-term books as soon as the airline’s schedule goes on sale and accepts the fare, knowing that demand for those dates only grows. A couple who can travel any week in November search a whole-month view, set an alert, watch for a few weeks and book a midweek departure when the fare matches the target they set. Neither approach depends on a magic booking day; both depend on understanding how much demand there is for the dates in question.
In short
- Peak and school-holiday dates: book early.
- Off-peak short-haul: watch, set alerts and book when the fare looks right.
- Long-haul peaks: book several months ahead.
- Flexibility on dates and airports beats trying to time the purchase.
