USD/US
USD/US
Flight price comparison sites don't always show the same price because of cached prices, booking-partner access, distribution deals, fare buckets/classes, and delayed fare updates.
Learn more about these pricing factors and see a current live-search comparison using five popular sites.
Flight price comparison websites show different fares, usually because of each site's relationship with airlines. Timing and distribution deals are the main reasons you see different prices on different sites.
Many people think your browser cookies can increase prices every time you look at a flight. This is a myth. Searching in incognito mode or a private browser won't make a difference. What will make a difference are these factors:
Every platform is a little different. To learn more, read our flight booking site reviews, including our full Skyscanner review.
Here's what a search across five different platforms produced:
Search Conducted in Seattle, WA on September 9, 2026.
Departing From: Seattle, WA
Flying to: Boston, MA
Departure Date: November 25, 2026
Return Date: November 30, 2026
Filters: Nonstop flights only
Sorted by: Cheapest
| Site | Airline | Price |
|---|---|---|
| Kayak | Delta | $588 |
| Google Flights | Delta | $538 CHEAPEST |
| Skyscanner | Delta | $588 |
| Momondo | Delta | $588 |
| Skiplagged | Alaska + Delta | $593 |
The cheapest fare in our five-site test was $538 on Google Flights. Kayak, Skyscanner and Momondo each showed $588, while Skiplagged showed $593.
The difference between the lowest and highest displayed fare was $55.
Note that a site like Skiplagged operates slightly differently. It searches for all flight paths that include your departure and arrival destinations, including ones where your final destination may be a layover during a longer flight. For example, you might book a flight from Seattle to Boston with a layover in Denver, but your actual destination is Denver, so you don't board the second flight. In some cases, this is actually cheaper than booking a direct flight to your destination.
For more platform comparisons, check FlightsFinder's own price-comparison research report.
To see whether the differences were limited to one search, FlightsFinder compared the same five platforms across four additional international routes.
The four additional searches were conducted on September 24, 2026. We compared the cheapest displayed fares found across Skyscanner, Kayak, Google Flights, Momondo and Skiplagged using the route, travel dates and flight filters shown below.
Across these five route searches, no single comparison site produced the lowest displayed fare every time.
Search dates: Seattle to Boston was searched on September 9, 2026. The four additional international routes were searched on September 24, 2026.
Largest difference: $205 on Phoenix to Rio.
Smallest difference: $12 on Dallas to Paris.
Average difference between the lowest and highest displayed fare across the five searches: $78.
| Reason | What it can mean for travellers |
|---|---|
| Cached prices | A displayed fare may not yet reflect the latest availability. |
| Booking partners | Different sites may search different sellers. |
| Fare buckets | One partner may have access to a cheaper fare class. |
| Distribution deals | Airlines may make different fares or inventory available to different partners. |
| Update timing | One platform may receive a new fare before another. |
| Different algorithms | Sites can combine airlines and flight options differently. |
Flight comparison websites can have different prices simply because they're different companies with different operating criteria. It's like why gas stations on opposite sides of town can have slightly different prices. Below are detailed explanations of the most important factors that impact prices.
Cached pricing is a simple concept. It means a website is showing stored flight-price information, so it hasn't been updated yet. A certain fare or seat type may sell out on the airline's website, and it can take time for flight price comparison websites to reflect the new inventory and current pricing. Booking partners may not all refresh at the same rate, causing discrepancies.
Sites also use different algorithms to mix and match airlines for departing and return flights. Not every site features every airline. Lower-end airlines, such as Frontier, Sun Country Air, and Spirit, don't show up on all platforms. This usually comes down to booking-partner access. Booking-partner access determines which airline and travel-agency fares a comparison platform can search, display or refer travellers to.
Another reason you may see different prices is due to fare classes, aka fare buckets. This refers to the different prices that can apply to the same seats. For example, an airline may have 20 economy seats, but 10 are priced at $150 on the airline website, and 10 are priced at $200 on partner sites. One booking partner might have access to a lower-fare bucket, so you'd see a different price when shopping around.
Distribution deals detail what fare buckets and seat inventory are available to which booking partners. Airlines may have more favorable deals with certain partners, making it difficult to know which site to use when booking a specific airline. For example, if Kayak and JetBlue have a favorable distribution deal, Kayak is likely to have the lowest prices on JetBlue sites (of course, that's just a hypothetical!).
Promotional pricing is a common part of distribution deals, which allow a specific booking partner or agency to offer a lower fare. These extra-low prices are usually only available for a short window and may appear at the top of your search results as a sponsored offer.
Priority booking partners usually get updated fare prices first. That's another reason sites might show different prices unrelated to your caching or cookies. Airlines distribute fares and availability through different systems and booking relationships, so some platforms may receive or display updated availability sooner than others.
If you know how to compare flight prices, you can save hundreds. Before you book, check the final bookable price (the one you'll see right before entering your credit card information), so you're not caught off guard by the total.
Don't be afraid to keep checking the same flight for price changes. Despite what some think, repeated searches don't increase prices, and searching in incognito mode doesn't change pricing, according to FlightsFinder's own price-comparison research.
The cheapest displayed fare isn't always the cheapest fare you can actually book. Always click through and check the final price, including taxes, baggage and booking fees, before entering your payment details.
No single site will always have the cheapest flights. If you want the best deal every time you take off, check multiple platforms to find the lowest price. It can take more time, but it can save you hundreds of dollars on your flights.
One way to save time while still searching all the top platforms is FlightsFinder, which lets you compare flights across multiple platforms in one place. You can check multiple sites on our flight booking comparison website without opening a million tabs.
Flight comparison sites don't necessarily search the same fares, booking partners or inventory at exactly the same moment. That's why the cheapest site can change from one search to the next.
The five-route FlightsFinder comparison above demonstrates why checking several platforms can reveal prices you might miss by relying on only one.
Common questions about why flight prices differ between comparison sites.
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