Ryanair has said that Google needs greater transparency in its online ads to ensure consumers are not misled.
The airline has taken issue with how ads for cheap flights are displayed on its search pages.
In a statement today, Ryanair said that websites known as screen-scrapers are consistently ranked above Ryanair's own site in searches.
Screen scrapers trawl airline websites for cheap fares and then sell them on to passengers through their own site.
Ryanair said that in some cases consumers buying through screen-scraping sites are unable to check in online - a particular problem for customers in Ireland and the UK.
They also do not receive up-to-date flight information as the airline does not have their contact details.
The airline has, in the past, sued individual screen-scraping sites most recently winning a case in a court in Germany against one such site - eDreams.
But it said it believes that Google is leading consumers to screen-scrapers and that some are misled into thinking they are dealing with Ryanair.
The airline has urged customers to book directly on Ryanair.com and called on Google to enforce greater transparency on its advertising rules, to prevent European customers being misled and overcharged.
"As Europe's largest airline, Ryanair has received numerous complaints from our customers who have inadvertently purchased Ryanair flights on the eDreams website, as a direct result of the misleading advertising provided by Google," commented Ryanair's Kenny Jacobs.
" While we have no issue with Google advertising in general, it is unfair that it is used as a mechanism to mislead customers," he added.
