The Claim That "Deleting Cookies Makes Flights Cheaper": I Investigated It to the End
"Delete your cookies and search again. They say it makes it cheaper."
My friend said this, and I wondered if it was true, so I searched and found that this idea is quite common. People say to open incognito mode, delete cookies, or search from a different device. But I was curious if it actually works or if everyone just follows along, so I looked into it thoroughly.
To tell you the conclusion first, it's half true and half false. Prices do sometimes go up, but it's not because of cookies. There's a real underlying cause, and knowing it can help you buy tickets cheaper than just using incognito mode. Please read to the end!
Honestly, I believed it at first too.
Since everyone said so, honestly, I initially believed that prices went up. I always booked flights in incognito mode. Some flight search platforms even state in their guides that "deleting cookies can help." The idea is that cookies track user behavior, and if the site determines "this person is serious about buying," it raises prices.
Looking at it this way, doesn't it make you think, "Aren't prices going up because cookie values are being saved?"
I looked into some data, and airline headquarters have a completely different stance. Skyscanner officially states that they do not raise or adjust prices based on cookies, location, or search history. A Korean airline official also stated in an interview with Sisa Week that "prices will not increase due to search history." Honestly, even at this point, I thought it would be much cheaper to use incognito mode, didn't you?
I'll share some interesting information now! According to an article that actually conducted an experiment, when the same flight was searched twice with a 40-minute interval without deleting cookies, the price sometimes even dropped. This means the price became cheaper without deleting cookies. This suggests that the idea of prices increasing after multiple searches is incorrect.
So, what really moves flight ticket prices?
The official industry term is Revenue Management system. Airlines recalculate prices daily, hourly. It's not cookies that change the price, but several variables.
Among many variables, the number of remaining seats is the biggest. Flight ticket prices are divided into different classes for each seat, right? When the cheapest class sells out, it automatically moves to the next class. So, if a seat that was 320,000 won yesterday is 380,000 won today, it's not because of cookies, but because someone else bought the cheaper class in the meantime.
The time remaining until departure is also a major factor. Prices change in stages, for example, once 6 months before departure, once 3 months before, and once 1 month before. Prices get more expensive closer to departure due to fewer remaining seats, and conversely, too early, like 6 months before, can also be expensive because only full fares are open.
The time of day you search also has an impact. Even if you search for the same flight on the same day, prices can differ between early morning and evening, because airlines run new demand forecasts for different times of day.
They also look at competitor airline prices. If airline A lowers the price for a route, airline B follows suit.
These four factors, not cookies, are what truly move prices.
However, personally, when booking flights for 2 or more people, I always check for 2 adults (the number of people going) instead of 1 adult. I feel like it's a bit cheaper that way. The price drops significantly. This is just my personal feeling!
Then why do people feel that flight tickets get more expensive the more they search?
It's a cognitive bias. Simply put, we usually search for flights right after we decide to travel, right? Then, over the next few days or weeks, prices naturally fluctuate, but people perceive it as "the price went up because I searched repeatedly." Because they don't look frequently otherwise.
Another reason is that seats are actually sold between searches. The remaining seat mechanism I mentioned earlier is at play. You might feel, "The price went up after I searched for just 5 minutes," but in those 5 minutes, someone else bought the last cheap seat. It's the market's doing, not cookies! When we search for flights, other people are probably searching too.
And honestly, I think it's true that on OTA sites (online travel agencies like Trip.com, Expedia), prices can temporarily appear different depending on cache or cookie settings. The industry doesn't officially admit it, but it happens. That's why some people occasionally feel that incognito mode "works." However, this isn't the airline raising prices; it's the intermediary platform showing cached prices or displaying different results based on user sessions.
So, I compare OTA sites, Naver Flights, etc., and then book on the airline's official website! I haven't traveled extensively, but I've always done it that way for my international trips.
Is incognito mode still useful?
It is useful. But the reason is different from what I mentioned earlier!
The real effect of incognito mode is simply that it "doesn't show cached screens from previous searches and retrieves real-time data." When you feel like the price you saw yesterday is the same today, going into incognito mode retrieves the actual current price. This is why prices sometimes appear different.
Searching in incognito mode isn't about "reverting prices that went up due to cookies to normal"; it's about "reconfirming the true price at this very moment." Knowing this difference changes everything.
And one more tip: even without using incognito mode, pressing Ctrl+Shift+R on the same page forces a refresh, ignoring the cache. This is the fastest way to check real-time price changes.
How to really buy cheap flight tickets?
This is the most crucial point. There are much more effective ways than deleting cookies.
That's price alerts. Almost all flight search platforms send email or push notifications for price changes on specific routes and dates. Setting up an alert is more efficient than searching every day, and most importantly, it frees you from the suspicion that "prices went up because I searched repeatedly" due to cookies.
Statistics often cite Tuesdays and Wednesdays as generally cheaper. However, this varies by route. And even within the same day, prices can differ if you search during early morning hours. I also tend to use early morning hours.
This is a bit limited, but also search for nearby airports. When going to Tokyo, don't just look at Narita; check Haneda too. When going to London, don't just look at Heathrow; check Gatwick and Stansted too. For the same city, different airports can have price differences of over 100,000 won. In fact, when I went to Tokyo, I saved money and the airport was less crowded.
If possible, try using stopovers. Connecting flights are often cheaper than direct flights. If the layover is 8 hours or more, you can even do some sightseeing in that city. However, you need to check visa requirements for the layover country in advance. This is recommended for those with a lot of time for travel.
So, what's the real conclusion?
The idea that "searching for the same flight twice makes the price go up" is more of an unverified rumor that has taken root among people. While some OTAs might show similar phenomena due to cache effects, airlines almost never track users to raise prices. The backlash if such a fact were revealed would be obvious!
So, instead of spending time in incognito mode, it's truly more effective to set up price alerts, determine your booking window by counting back from the departure date, and check nearby airports and connecting options. When and at what point you buy the ticket influences the price more significantly than how you search.
There are surprisingly many factors to consider for flight tickets, just like accommodation. I hope my post helps you purchase flight tickets at a lower price.