The US-owned engine, which launched in the UK in December 2006, received over half of its inbound traffic (54%) from Cheapflights.co.uk in the first week of January and ensuring overall UK visits have doubled since Christmas.
Hitwise data also revealed Kayak was the number one outbound site from Cheapflights in the first week of January, accounting for 12% of downstream traffic.
Kayak has reaped the rewards of an agreement signed in December last year with Cheapflights to become one of the main flight partners across the price comparison site’s booking engine.
Kayak’s other main referral site, but trailing significantly behind Cheapflights, is Google with a 13% share.
The Kayak system has also previously partnered with Cheapflights on the US website.
Meanwhile, Cheapflights has announced it has made a “strategic investment” in Icelandic global flight planner Dohop.com.
Dohop.com was created in 2004, using cutting edge Ajax functionality, in a bid to provide free flight planning tools for consumers, with links direct to airlines and online travel agencies.
Vice chairman and head of international at Cheapflights, Hugo Burge, said: “As one of the two oldest established travel websites, we at Cheapflights believe that our own experience in building an international web business will help provide the management expertise, industry contacts and consumer focus to help drive the future world growth and success of Dohop.com.
“This is a perfect tool for those who need to know precise flight times, routes and availability from anywhere to anywhere else.”
Burge and Cheapflights chief executive recently made a private investment in travel social networking site WAYN.com.