One flight, 35 prices: Dutch study debunks browser cookie myth

Another myth has been busted: clearing your browser cookies or switching devices before booking a flight will not save you a penny. While prices for a single seat on a flight can fluctuate up to 35 times during its sales window, a new market study has confirmed that popular browsing tricks have zero impact on what airlines charge. 

Deleting cookies won't get you a cheaper flight

Many travellers in the Netherlands routinely clear their browser cache, open incognito tabs or switch devices when booking trips, hoping to avoid price spikes. 

A recent study by the Netherlands Authority for Consumers and Markets (ACM) shows that nearly half of consumers (46 percent) mistakenly believe that earlier search queries drive up ticket costs, while 25 percent are convinced that the device used affects the final quote. However, the survey has confirmed that these digital tricks do not actually change the price.

While personalised pricing, which tailors costs to individual user data and online behaviour, is technically possible, the ACM noted that airlines currently restrict this practice to opt-in loyalty programmes. Standard ticket price fluctuations are instead driven by broader supply, demand and automated algorithms.

Single flight seat prices fluctuate up to 35 times

Ultimately, the study revealed just how unpredictable airline pricing has become for travellers. On average, airlines change the price of a seat on a single flight between 30 and 35 times throughout its sales window. In fact, one in three tickets ends up being sold at 40 percent or more above the average fare.

Ticket prices also follow a specific timeline. According to the report, average fares tend to decrease gradually as the departure date approaches, before rising sharply starting around two months before takeoff.

These continuous price swings leave many consumers feeling uncertain and overwhelmed during the booking process. The report notes that this dynamic pricing model creates extra search stress and places people with tight budgets or rigid schedules at a severe disadvantage.

Dutch regulator demands algorithm transparency as AI expands

To counter these hidden pricing tactics, the ACM is calling for strict transparency laws to force companies to open the "black box" of their algorithms.

"We expect that, because of AI and the availability of data, companies will use computer-controlled prices more frequently, including personalised prices," ACM Chairman Martijn Snoep told NOS. He emphasised that clear regulations are needed to foster public debate and prevent automated systems from exploiting consumer vulnerabilities.

Dynamic pricing is rapidly expanding beyond aviation to webshops, concert tickets and petrol stations. The watchdog insists that people in the Netherlands should know exactly which factors dictate what they pay, and its draft report remains open for public consultation until November 9, 2026.