It offers tailor-made travel guides fully integrated with Google Maps (which itself already allows hotel bookings) and if you use Gmail, not only will it will pick up previous bookings and display them in its search results, it will also put them into a new app called Google Trips.

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Until now, the main markets for Google Flights, Kayak and Skyscanner have been the US and Europe. “One reason is that flight metasearch becomes much more useful when you have lots of airlines,” says Maggie Rauch, senior director for research at Phocuswright.

“That makes metasearch a less compelling option in China, Japan, Korea, Australia, and India, except for when it comes to international flights.” However, she adds, all three flight search companies are now going after travellers in Asia-Pacific markets. “The opportunity is changing as more Asian travellers go overseas,” she says.

It is not surprising that Google has the best technology out there. “Google is known for delivering results very quickly, and speed is something all metasearch platforms chase,” says Rauch. “But also key to users is how the information is delivered – how easy is it to compare flights and fares, and how do they enable to you to explore destinations or choose the best dates based on your needs and budget.”

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Geography also plays a role. While Google is banned in China, Skyscanner is now owned by Chinese travel services provider Ctrip, the world’s second largest online travel agency.

“Skyscanner is the smallest player of the three – its biggest impact is in Europe, but it is also expected to grow significantly in Asia since becoming part of Ctrip,” says Rauch.

It also has plans to match Google Flight’s provision of destination guides. “Travellers are increasingly looking for personalisation,” says a SkyScanner spokesman. “In light of this, we will be launching personalised, hyper relevant, in-trip content to travellers, using the technology, community and content behind Trip.com.”

Renamed from Gogobot, Trip.com is a discovery app owned by Ctrip.

For now Google Flights and Kayak remain the major players in this market. “Google Flights and Kayak are the gatekeepers, commanding significantly more visits than smaller players,” says Rauch.

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It displays the likelihood of your flight price rising within a week, based on historical data, so you can decide whether to book now or wait.

“But when Google does send travel shoppers on to airline sites and online travel agents, they are more likely to actually make a booking,” says Rauch. There is quite a difference; Phocuswright’s research with Jumpshot shows that Google Flights hit a 25 per cent conversion rate in April 2017, compared to 7 per cent for Kayak.

With that growth spurt, a speed advantage, and integration with so many of its other apps, you can’t help thinking that, outside China, Google Flights’ journey has just begun.