Greenlight Search checked the rankings for 3,200 generic and destination-specific keywords, which resulted in 5.5 million queries during March.
Other top-performing sites included Skyscanner and Travelsupermarket, followed by Lastminute.com and Dealchecker.
Last year, a study by search engine marketing firm NetCallidus revealed that British Airways (BA) had the best UK airline site in terms of search engine optimisation, followed by easyJet and TUI.
Mark Furber, managing director of NetCallidus, said BA's success was down to the fact that it had more pages indexed by Google than its competitors, as well as a significantly higher number of incoming links from other websites.
Direct News