The cheapest flight can cost you more.

Start with the same trip

Put two or three options side by side using identical dates, travellers and baggage needs. Check the exact airports, not just the city names. A convenient arrival at the wrong airport for your hotel can change the transfer cost considerably.

Record the final payable amount after selecting what you actually need. A seat, meal or checked bag may be an optional extra rather than a reason to reject a fare; the point is to compare equivalent baskets.

Add the costs outside the ticket

Include transport to your departure airport and from the arrival airport to your stay. An early departure may mean a taxi instead of your usual public transport. A late arrival may require a different transfer or another hotel night.

Check baggage against the specific fare and operating airline. IndiGo, for example, states that free checked baggage, when applicable, depends on the tariff or promotional fare. Never carry an allowance from an old trip into a new booking without checking.

• Fare and taxes for every traveller
• Bags and any extras you choose
• Airport transfers at the actual travel hours
• Any extra room night created by the schedule

Price the time you lose

Write down when you can realistically reach the hotel, eat and begin your trip. Landing at noon does not create a full sightseeing day. Equally, a dawn departure can use up most of the previous evening if the airport is far away.

For connections, establish whether the itinerary is sold as a through journey or involves separate bookings. Read the arrangements for baggage, terminal changes and missed connections before deciding the saving is worthwhile. There is no single connection buffer that fits every airport and itinerary.

Make the final check before paying

Confirm passenger names against the travel document, the date on each flight, airports and the selected baggage. Read the change and cancellation terms for that fare, including how any refund would be returned.

Save the confirmation and check that the booking appears with the airline. Choose the option whose total cost and timing suit your trip; a modestly higher ticket can still be the better overall purchase.