Flight search results are sorted by price, which is the one number that tells you least about whether the trip will be any good. Nine things are worth checking before you compare fares at all — and most of them move the real cost more than the fare difference does.
1. The airport, at both ends
A city can have several airports and they are not interchangeable. Paris Beauvais is roughly 85 km from Paris. Milan Bergamo, Stockholm Skavsta, Frankfurt Hahn and Toronto Hamilton all carry the name of a city they are a long way from. At the other end of the scale, London City, Tokyo Haneda and Chicago Midway are all closer to the middle of town than the main airport.
Price the transfer at each end, add it to both fares, then compare. The cheap flight loses more often than people expect.
2. Whether it is one ticket or two
This is the single most consequential thing on the page. On one ticket, if a delayed first leg makes you miss the second, the airline must rebook you. On two separate tickets, you are simply a no-show for the second flight and must buy a new one.
Self-connecting itineraries assembled by a search engine can be genuinely cheaper. Just know which kind you are buying, and if it is two tickets, leave hours rather than minutes — or an overnight.
3. The connection time, against the right benchmark
On a single ticket, the airline's own minimum connection time for that airport is a reasonable floor, and more is better at large hubs where you may change terminal, clear immigration or re-check a bag. Connections that involve changing airport are always effectively separate tickets — treat them as a travel day, not a layover.
4. What the fare actually includes
Basic-economy fares now exist on most airlines and no two are the same. Before comparing, check four things on each:
- Is a cabin bag included, or only a personal item under the seat?
- What does a checked bag cost, each way?
- Is seat selection paid — and does it matter to you? (It does if you are travelling with a child.)
- Can the ticket be changed at all, and at what cost?
A fare $60 cheaper that adds $45 each way for a suitcase is $30 more expensive. This is the most common way people pay more while believing they saved.
5. Total elapsed time, not flight time
A 6-hour itinerary with a 55-minute connection and a 14-hour itinerary with an overnight in a hub are different products. Note the arrival day as well as the time; overnight flights arriving at 06:00 cost you a hotel night or a day of exhaustion.
6. Aircraft and seat, for long flights
On anything over about six hours this is worth two minutes of your time. Seat width and pitch vary meaningfully between airlines and between aircraft types on the same airline, and a narrow-body operating a long route is a different experience from a wide-body. Look up the specific aircraft for your flight number rather than the airline's general product page.
7. Who you are actually buying from
Three kinds of site sell flights and the difference matters when something goes wrong:
- The airline. One party, able to rebook you on the spot, legally responsible for operating the flight.
- An online travel agency. Can combine airlines on one booking and sometimes beats the airline on price. Changes go through them, which adds a step and, during mass disruption, a queue.
- Metasearch. Sells nothing; compares and hands you on. Check where it is sending you before entering a card, because that is who you are buying from.
There is no universally right answer, but for a complicated or expensive trip, buying from the airline buys simplicity when it matters.
8. The rules that apply if it is cancelled
Passenger rights differ by jurisdiction and by where the flight starts and which airline operates it. Rather than assuming, check what applies to your specific routing before you book — and note that the operating carrier, not the one whose code is on the ticket, is usually the responsible party. If two options are close on price, the one covered by a stronger scheme is worth a little more.
9. How you are paying
Credit cards carry purchase protection in many countries that debit cards and bank transfers do not, which matters more for flights than for most purchases because airlines occasionally fail. Check for a card surcharge, and check whether the site is quoting in your own currency or offering a conversion — the conversion is almost always worse than your bank's.
A workable order of operations
- Decide the acceptable airports at both ends and the acceptable arrival window.
- Search metasearch to find out what routings exist.
- Shortlist two or three, then price each including bags, seats and transfers.
- Check whether each is one ticket or several.
- Book the winner, preferably direct with the operating airline.
- Screenshot the fare conditions at the moment of purchase.
What not to bother with
There is no good evidence that clearing cookies or browsing privately changes the fare you are shown. Prices move because seats in a fare bucket sell out, not because a site recognises you. Time spent checking a route across a few different dates is far better spent than time spent managing your browser.
Common questions
What is the difference between one ticket and two separate tickets?
On a single ticket the airline is responsible for your connection and must rebook you if a delay makes you miss it. On separate tickets you are a no-show for the second flight and have to buy a new one. Always check which you are buying.
Does booking on a Tuesday get cheaper flights?
No. Fares change when seats in a price bucket sell out, not on a weekly cycle. Checking a route across several departure dates is far more productive than trying to time the day of booking.
Is it better to book with the airline or an online travel agency?
Neither is reliably cheaper. Booking with the airline means one company to deal with if the flight changes, which is worth a lot during disruption. An agency can combine airlines onto one booking that the airlines themselves would not sell you.
How much connection time should I leave?
On one ticket, the airline's minimum connection time for that airport is the floor, and more is better where you change terminal or clear immigration. On separate tickets, leave several hours or an overnight, because nobody is protecting the connection.
Sources
Journey times, operators and transfer options on this page were checked against these sources on 11 September 2026. Operators change timetables and fares without notice — always confirm on the operator’s own site before you commit to a plan.
