Got your eyes on your dream holiday overseas? Before you pack your bags, you’ll need to sort out your airfares. But which is the best – and cheapest – way to go, booking directly with an airline or using a third-party booking site?

A growing business

The popularity of booking flights online has taken off in recent years. According to market research firm Euromonitor, online flight bookings made in New Zealand were worth $3994 million last year, compared with offline sales of $2498m.

While most bookings are still made directly with the airlines, third-party operators are gaining ground. Of all online sales last year, $543m were through third parties, a rise of 41 percent since 2009.

Expedia, Flight Centre, House of Travel, Webjet and Expedia-owned Wotif are among the companies getting a slice of the action.

However, the growth in popularity of third-party booking sites has led to a push-back from some airlines. For example, Delta Airlines in the US recently pulled its data from a number of sites. Lufthansa Group now charges a US$18 fee for bookings made outside its website.

This means you can’t assume a booking site is accessing all available airlines.

What’s cheaper?

Comparing prices isn’t always easy. Extra fees mean you often have to fork out more than just the headline price. This can also mean sites offering cheap flights don’t necessarily have the best deal.

We looked to see if there was a price difference between the sites offering cheap deals and booking directly with the airline for the same return flight.

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Extra fees

As well as the ticket cost, the third-party booking sites we looked at nearly all charged online booking fees.

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Price changes

Be aware that great price you saw advertised may not be guaranteed until your ticket is issued. Third-party booking sites may have clauses in their terms and conditions that state prices are subject to availability of seats.

However, sites operating in our market are also subject to our consumer laws - the Fair Trading Act and the Consumer Guarantees Act. This means they can’t mislead you or make false representations and must carry out their services with reasonable care and skill.

Report by Kate Sluka.