For years, travelers have been told the same trick: wait until Tuesday to book your flight because that is when airlines supposedly offer their cheapest tickets.
It is one of the most persistent travel tips on the internet.
There is just one problem. There is no longer a universal cheapest day to book a flight.
Airline prices now change constantly, sometimes several times in a single day, as sophisticated pricing systems react to demand, remaining seats, competition and the amount of time before departure.
So if Tuesday is not the secret, what actually helps you find cheaper flights?
When should you book?
Timing still matters, but the number of days before departure is generally more important than the day of the week when you press the purchase button.
Google Flights says airfare does not change dramatically depending on which day travelers make their booking. Its historical analysis has found Tuesday to be only slightly cheaper than Sunday, making it unlikely that waiting specifically for Tuesday will produce a major saving.
For domestic trips, buying several weeks before departure is generally safer than waiting until the final days.
International flights usually require even more planning. Depending on the route and season, attractive fares can appear months before departure.
The biggest mistake is often waiting for a magical booking day while the price of a good flight continues to rise.
The day you fly matters more
This is where travelers can find more meaningful savings.
Flights departing during the middle of the week are frequently cheaper than those leaving around the weekend.
Google's historical airfare analysis has found that flying on Monday, Tuesday or Wednesday has been cheaper on average than weekend travel.
That means changing your departure date by one or two days can sometimes save considerably more money than changing the day on which you buy the ticket.
Be flexible with airports
A second airport can completely change the price of a trip.
Someone visiting London, Paris, Rome or another major city may have several airports to choose from. A cheaper flight into a secondary airport can look attractive, but travelers should calculate the cost of reaching the city before booking.
A €40 saving on airfare becomes meaningless if airport transportation costs an additional €50.
The same strategy applies at your departure point. Checking airports within driving or train distance can reveal fares that do not appear when searching only from your nearest airport.
Compare dates, not just airlines
Instead of repeatedly searching one exact itinerary, use a flexible date calendar.
Moving the trip one day earlier or later can expose significantly different prices, particularly during holidays and school vacation periods.
Price tracking can also help. Google Flights allows travelers to track fares for specific dates and routes and receive notifications when prices change.
This removes much of the guesswork from deciding whether to buy immediately or wait.
Avoid the obvious expensive periods
Christmas, New Year, Easter, major sporting events and school holidays create predictable surges in demand.
If thousands of people want the same seats at the same time, there is little reason for airlines to discount them.
Traveling immediately before or after these peak periods can sometimes make a dramatic difference.
The same principle applies to destinations themselves. Visiting popular European cities during shoulder seasons such as spring and autumn can mean cheaper flights as well as lower accommodation prices and smaller crowds.
Is booking at midnight cheaper?
There is no reliable evidence that opening an airline website at midnight automatically unlocks cheaper tickets.
The same applies to another popular internet claim: repeatedly searching for a flight will necessarily make the airline raise the price specifically because it knows you are interested.
Airfares genuinely move up and down, but changes can result from inventory, demand and dynamic pricing rather than simply one person performing another search.
The best strategy is surprisingly simple
Do not wait for Tuesday just because an old travel rule says you should.
Instead, start checking early, compare several dates, consider nearby airports and track the fare.
If your travel dates are flexible, experiment with the day you actually fly rather than obsessing over the day you make the booking.
There may no longer be a secret day when airline tickets suddenly become cheap.
But flexibility remains one of the closest things travelers have to a real airfare hack.
