There is a specific kind of flight search that only KAYAK handles well: I need to be in Porto on Thursday morning, I will not connect through Heathrow, I want a checked bag included, and the layover has to be under two hours. Google Flights will shrug at most of that. KAYAK has a checkbox for all of it.
Filters as the product
The filter rail is the reason to use KAYAK and it is not close. Beyond the usual stops-and-times controls, you can constrain by:
specific connecting airports, included or excluded
minimum and maximum layover duration
airline alliance
whether a checked bag is included in the displayed fare
aircraft type, on many routes
overnight-flight exclusion
Combine four of these and the result set drops from three hundred itineraries to eleven, all of which are actually acceptable to you. That is the difference between a search tool and a list.
Explore, Hacker Fares and the forecast
Explore takes a departure airport and a rough time window and paints fares onto a map. It is the best "where can I go cheaply" tool that is not attached to a subscription, and it handles month-level flexibility gracefully.
Hacker Fares pair two separate one-way tickets when that combination beats a return. The saving is sometimes significant. The risk is the one KAYAK does flag but that people ignore: two separate tickets are two separate contracts. A delay on the outbound does not obligate the second airline to do anything.
Price Forecast offers a buy-or-wait recommendation with a confidence level. Treat it as directional. It is better than intuition on stable routes and less useful on volatile ones, and no forecast on any platform has ever been reliable enough to bet a trip on.
The seller problem
Here is where KAYAK costs itself points. Because it lists everyone, the cheapest row on a KAYAK results page is often an online travel agency with a thin trading history, a support line in a distant time zone, and terms that make a schedule change your problem. The saving over the airline's own fare is frequently £15–40.
That is not KAYAK's fault in a narrow sense — it is showing you the market. But a metasearch that sorts by price and leaves you to evaluate counterparty risk is handing you a decision it has the data to help with and does not.
Our rule, and it has saved more money than it has cost: if the cheapest seller is not the airline, and the gap is under about five per cent of the fare, book with the airline. On a schedule change, cancellation or missed connection, having a direct contract with the carrier is worth more than the difference.
The cheapest ticket you cannot change is not cheaper than the ticket you can.
Hotels, cars and the rest
KAYAK also does hotels and car hire. Both are competent and neither is a reason to be here. Hotel results are thinner than Google's and the direct rate appears less often; car results are reasonable but Discover Cars and the dedicated brokers give you better total-cost visibility.
There is also an ownership note worth stating: KAYAK belongs to Booking Holdings, which also owns Booking.com, Agoda and Priceline. Those are among the sellers KAYAK lists. As with trivago and Expedia, this is disclosed and does not appear to distort results in any way we could measure, but a reader comparing "independent" metasearch options should know that almost none of them are independent.
The features nobody uses and should
Three things are buried in KAYAK's interface and are worth finding.
Price alerts on a filtered search. You can set an alert not just on a route but on a route with your constraints applied — nonstop only, bag included, specific airports. That turns the alert from noise into something actionable.
The Best Time to Travel view, which shows fare seasonality across a year rather than a month. For someone planning a big trip twelve months out, it is more useful than any daily price graph.
Trips, KAYAK's itinerary organiser, which parses confirmation emails much as TripIt does. It is not as accurate as TripIt and it is free, which for occasional travellers is the right trade.
Where the filter set earns its keep
The clearest example is a family booking. Four people, one of them a child, two checked bags, no connection under ninety minutes because you will not make a tighter one with a toddler, and no red-eye.
On Google Flights that search is four separate mental filters you apply by eye to a list. On KAYAK it is four checkboxes, and what comes back is a set of itineraries that would all actually work. On a booking worth two thousand pounds, spending ten minutes in a denser interface to avoid a ninety-minute connection with a four-year-old is obviously the right call.
That is the case for KAYAK in a sentence: it is worth the extra complexity in proportion to how many constraints you genuinely have.
Verdict
KAYAK earns 7.8 for doing one thing better than anyone: letting a traveller with real constraints express them and get a usable answer. The interface is dense, the filters are deep, and Explore is genuinely enjoyable to use.
It loses ground on the last mile. Sorting a mixed field of airlines and consolidators purely by price, without weighting for who you will be dealing with when the flight moves, pushes a risk onto the user that the platform is better placed to assess. Use the filters, ignore the bottom line, and read the seller name twice.
