Here is an uncomfortable fact for the airlines: their own websites are rarely the cheapest place to buy their own seats. I ran a Manchester–Bangkok return through nine tools last month, and the spread between the highest and lowest price for the exact same itinerary was about £180 — with the airline’s own homepage sitting firmly in the upper third.
That gap is not magic. Metasearch engines and aggregators pull from dozens of online travel agencies, consolidator fares, and regional pricing that carriers never surface on their tidy direct-booking funnel. The trick is knowing which to open first, because they are not interchangeable — each has a blind spot. I have ranked the seven I keep in rotation, roughly in the order I open them; the numbers are illustrative, the strengths and weaknesses consistent.
1. Google Flights — the one you open first
Google Flights is fast, clean, and frighteningly good at the thing that matters most early on: showing you where the cheap days are. The “Date grid” and “Price graph” let you slide departure and return around until the fare stops twitching, turning a vague “sometime in March” into a precise “the 12th to the 19th is £90 less than the 5th.” No other tool does this as smoothly, so I lock down when to fly before worrying about who with.
Run your route through Google Flights with flexible dates to find the cheapest week, then take those exact dates to the other tools below. Searching fixed dates everywhere wastes the one thing Google does best.
The catch: Google Flights shows fares but usually hands you off to the airline or an OTA to pay, and it omits a few carriers entirely. Treat it as reconnaissance, not the final word. For the full head-to-head, I broke down how Google Flights and Skyscanner stack up on the same five routes — they disagree more often than you would think.
2. Skyscanner — the widest net for budget carriers
Where Google plays it establishment, Skyscanner scrapes the scrappy corners — the regional low-cost carriers and obscure OTAs the big engines skip. Its “Everywhere” search, which ranks every destination on earth by price from your home airport, is unbeatable for the traveller who cares more about the bargain than the place.
The whole-month view is genuinely useful, and its coverage of budget airlines in Asia and Eastern Europe is a cut above — I have repeatedly found fares Google flatly did not list. The downside is the hand-off: Skyscanner often routes you to third-party agencies of wildly varying quality, with refund policies written in fog.
3. Momondo — the one that finds the weird routings
Momondo (same parent as Kayak, but it behaves differently) has a knack for the slightly-mad itineraries that save real money: mismatched carriers each way, a self-transfer through a third city, an obscure consolidator fare. Its results often undercut the others by £20–£40 precisely because it suggests things a cautious engine won’t.
I open it third, mostly to check whether anyone is beating my Google-plus-Skyscanner number — and to spot the self-transfers worth a closer look before I trust them.
4. Kayak — the aggregator’s aggregator
Kayak’s strength is breadth and filters. It pulls hundreds of sources and lets you slice by layover length, airport, cabin, and bag fees with more precision than most, and its “Hacker Fare” feature explicitly builds cheaper one-way combinations.
It is rarely the single cheapest, but it is the best for sanity-checking. If Skyscanner shows me a £210 fare and Kayak agrees within a few pounds, I trust it; if Kayak can’t find it at all, I get suspicious of the OTA behind it.
5. Kiwi.com — virtual interlining, for better and worse
Kiwi built its identity on “virtual interlining” — stitching together airlines with no commercial relationship into one bookable trip and guaranteeing the connection itself. This produces absurdly cheap routings no airline would sell you directly, occasionally undercutting the nearest competitor by a third.
The trade-off is real, so I will be blunt: you are now Kiwi’s customer, not the airline’s. Their guarantee covers rebooking on missed self-transfers, which is what makes this defensible, but service complaints are common — read exactly what it includes before you commit.
A foreign-based OTA may offer to charge your card in your home currency. That almost always carries a worse rate — the same skim I covered in how dynamic currency conversion quietly pads the bill at the card machine. Always pick the currency the fare is priced in.
6. ITA Matrix — the power tool nobody markets
ITA Matrix, run by Google, looks like it was designed in 2004 and behaves like a spreadsheet for nerds, and you cannot book on it. It earns its place because nothing else gives you this much control over how a fare is constructed — routing codes, specific connection cities, fare-class breakdowns, nearby-airport matrices all at once.
I use it when hunting something specific: the cheapest way to position into a major hub, or whether routing through a particular city shaves the long-haul price. Once it finds the magic combination, I rebuild that exact itinerary on Google Flights to pay. It is overkill for a simple weekend, but for a complex, expensive trip where £100 is on the table, it is the most powerful tool here — and the one fewest casual travellers know exists.
7. Going (formerly Scott’s Cheap Flights) — for fares you didn’t search for
The first six are pull tools: you ask, they answer. Going is a push tool — it watches routes for you and emails when a genuine mistake fare or deep sale appears from your home airports. Letting the deals find you rewards flexibility on destination and dates rather than a fixed plan, and the paid tier surfaces premium-cabin and rarer error fares. It is the only tool here that has made me book a trip I was not even planning.
It also pairs neatly with a points strategy: when a cash fare is mediocre, a flagged award sale can be the better play, which is the premise behind building a usable miles balance without ever stepping on a plane.
If you remember one thing, make it the stack: Google Flights to find the date, Skyscanner and Momondo to find the fare, an alert tool to catch the drop. Here is that logic in a grid.
| Tool | Best at | Watch out for | Book on it? |
|---|---|---|---|
| Google Flights | Flexible dates, speed | Skips some carriers | Often hands off |
| Skyscanner | Budget & regional coverage | Unknown OTA quality | Hands off |
| Momondo | Odd cheap routings | Self-transfer risk | Hands off |
| Kayak | Filters, sanity-check | Rarely the cheapest | Hands off |
| Kiwi.com | Virtual interlining | You’re their customer | Yes (with guarantee) |
| ITA Matrix | Routing control | No booking, steep UI | No |
| Going | Deals find you | Needs flexibility | No (alerts only) |
None of these is a silver bullet; any article promising one is selling something. The saving comes from two or three tools and the discipline to flex your dates before you flex your wallet.
Is it safe to book through a third-party site instead of the airline?
Often, yes — but it varies. Established agencies are fine; the no-name OTA at the bottom of a results list is where change fees, slow refunds, and support headaches live. For a complex or expensive trip, paying a few pounds more to book direct is cheap insurance.
Do these tools show me a different price than other people see?
The persistent-cookie price-gouging story is mostly myth; I have never reproduced a meaningful difference in a controlled test. Prices move because of live availability and currency, not because the site remembers you. Incognito won’t hurt, but don’t expect it to perform miracles.
Which one should I open if I only have time for one?
Google Flights for a fixed plan, because the date flexibility alone usually beats booking blind. Skyscanner’s “Everywhere” search if you are flexible on destination and chasing the lowest possible fare anywhere. Different jobs, different tool.
Treat the airline’s own website as the last tab you open, not the first — the place you confirm a fare you found cheaper elsewhere. Run your route through two or three of these, give the dates room to move, and that £180 spread tends to fall on your side of the ledger.
