Shall I buy airline tickets or wait more?

This is the question I ask myself every time when planning my holiday trips. Usually I know ahead of time the flight and the dates of my trip. So my challenge is to ..

Pick the best time to buy the tickets.

This time instead of making an emotional decision, I decided to throw some numbers at the problem and apply some stuff I learned in the data science field. Don’t worry, there will be no formulas ahead.

There are not many flight options for my route so I always go with beloved Ryanair. Here I am not being ironic. Some complain about their service, but if you know what to expect and follow the rules, you can get quite good price-quality combination.

The first example is around Tallinn-Girona flight with the departure on August 22, 2014. I tracked the price for this flight daily during more than two months and here is the outcome.

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Notice that the price does not move smoothly, there are clearly defined price corridors. During 41 days the price stayed at 91.99 € which seems to be the standard summer price for this flight.

As a reference, full up-to-date price stats for this route can be see at the below page.

There was only one day July, 25 when the luckiest could have purchased the ticket for the cheapest price. Notice that in each step the price increased approx 19% from the previous price. If you waited until the last moment, 4 days before departure you would pay more than twice than the luckiest passenger that may be sitting next to you.

Obviously the closer to the departure it gets, higher prices go. However one important observation can be made from the chart.

It is not always cheaper to buy too early

In my example if you to buy on June, 2 you’d pay the default price 91.99 €. If you waited just a few more weeks, but the end of June the price went down to 64.99 €. Multiple it by the number of family members and it will make quite a difference.

This is due to the yield management mechanism Ryanair as most of others airline have in place. That means there were not enough tickets sold by that day and the price went down. This behavior is confirmed by the research of BBC done in 2013. They observed similar pattern for Ryanair, EasyJet and British Airways.

I went deeper into the numbers trying to answer my main question. On a given day, what are the odds that you may find a cheaper fare in the future. In other words,

shall I wait or buy now?

To answer this, I aggregated the data for all departure dates of 5 popular routes for summer 2014. For a given observation date, I recorded the price on that day and checked what happened to the price later. In case it went down at least once, we say it is worth waiting. For each day prior to departure, I calculated what I defined as wait index, which is the

probability to find a better rate in the future.

The following charts shows how this probability declines as you get closer to the departure.

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Here are some observations which can be made:

  • 80 days before departure your chances to find better fare later are 80%
  • 35 days before departure your chances to find better fare go below 50%
  • 20 days before departure your chances to find better fare drops sharply


The price of budget airline flights does not only grow over time. In the example of Ryanair, it was demonstrated that there are periods when it may actually decrease if you to wait. This study suggests that it is fairly safe to wait up to 80 days before departure. If you are patient enough to wait up to 35 days before departure, there is still 50% chance to find lower fare later. There are still options to find low fares if you to wait longer, but the odds start playing against you. So if you are hunting for low fares now, check how many days are left to the departure and check you odds from the chart.

Update (Feb, 2015)

Just launched the website which simulates the features shown in this article. Based on fare stats, one can pick any Ryanair flight and get the probability of whether to buy now or wait.

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Written by

CTO, data scientist

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