GTM will continue to work alongside Kayak and Bezurk, an Asia-Pacific focussed meta search site, but will handle searches for all European flights and also power all queries for European users from the Lonelyplanet.com homepage.
The switch marks a major milestone point for GTM after just 18 months on the scene.
Kayak will handle the Americas and Bezurk will take on Asia-Pacific duties.
Lonely Planet has poured a huge amount of effort into its online services in recent months. Last week it launched a video sharing system, Lonely Planet TV, which allows users to rate and comment on content.
Booking and services manager at Lonely Planet, Mike McDermott, said: “The ability to provide an interface that provides a quick and user-friendly way for users of Lonelyplanet.com to search multiple travel sites and find what they want was the major reason for selecting Global Travel Market.
“Lonely Planet also considers the Global Travel Market platform also provides also the best array of European information of any meta-search site in this region.
The company was created by ex-Quest Travel boss Dave Simmons and is based in London.