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Why Do Flight Prices Change Every Time You Search?

You search a flight. The price looks decent. You open a new tab to check something else, come back five minutes later, and the same flight now costs £40 more. Or less. Either way, it feels like the website is watching you.

Here's what's actually going on — and what's just an internet myth.

The real reason: airlines sell the same seat at different prices, on purpose

Every flight isn't one price — it's several. Airlines split each flight into "fare buckets," a set number of seats priced at £310, another set at £340, another at £380, and so on. As each bucket sells out, the airline's system automatically starts showing the next one up.

So if you see £340 in the morning and £380 that evening, it's very possibly not that the price changed — it's that enough other people booked the £340 seats in between that the bucket emptied. Nobody targeted you. The seat you saw simply isn't there anymore, and the next cheapest one is.

This also explains why prices sometimes drop rather than rise: airlines release more seats into a cheaper bucket to fill a flight that's selling slowly, especially as departure gets closer for routes with spare capacity.

The second reason: a lot of "search" isn't actually searching

Not every travel site queries the airline live when you hit search. Many show a cached number — a snapshot pulled from the airline at some earlier point, sometimes hours old, sometimes from the previous day. It looks like a real-time result. It isn't.

That gap between what's shown and what's actually bookable right now is where most of the "the price changed the second I looked away" frustration actually comes from. It's not that the price moved in the five minutes since you last checked — it's that what you were shown the first time was never quite live to begin with.

What about the "clear your cookies, they're tracking you" advice?

This is the most common theory, and it's worth being straight about it: there's no solid public evidence that airlines raise prices based on your search history or browser fingerprint. Several airlines have explicitly denied doing it, and nobody's produced a documented, repeatable case proving otherwise. The fare-bucket explanation above accounts for the vast majority of what people attribute to "tracking."

That doesn't mean personalized pricing could never exist anywhere in travel — dynamic pricing based on demand signals is real and well-documented. But "searching too much makes your specific price go up" specifically isn't something that's been reliably shown to be true. Worth knowing before you start browsing in incognito mode expecting it to save you money — it likely won't, because it's not solving the actual mechanism.

What actually helps

• Prices genuinely move fastest close to departure and on popular routes — if a flight is filling up, don't expect the price you saw yesterday to still be there today.
• A live price is only a live price if it was queried live. Cached comparison sites can't tell you a bucket just sold out ten minutes ago — only a real-time query can.
• If you see a fare that fits your budget, that's the moment to act on it, not a signal to keep refreshing hoping it drops further. It might. It might also be gone.