Screen scraping is the term used for one website's automatic gathering of information from another website. Many websites in the airline and insurance businesses welcome screen scraping by aggregators as a way of generating new business, but Ryanair opposes the practice.
It has just begun a case in Dublin's Commercial Court against Bravofly aimed at stopping it from using Ryanair's data. Bravofly is a search and booking service for budget airlines.
Ryanair is claiming that Bravofly's alleged activities break laws on trade marks and copyright and amount to 'passing off'.
"We are taking this case because their behaviour violates our terms and conditions which state very clearly that you can't make any commercial use of our website," said a Ryanair spokesman.
Ryanair has asked the court for an injunction preventing Bravofly from continuing its activities and for exemplary damages and an account of profits for alleged interference with Ryanair's economic interests.
Ryanair has previously complained to Lastminute.com about its practices, alleging that that firm was engaging in screen scraping.
The Ryanair spokesman also told OUT-LAW that the company was in the late stages of a similar case in Germany where the company had taken action against an alleged screen scraper, though the results of the case are not yet known.
Other airlines have taken similar action in the past. EasyJet confirmed last month that it had sent warnings to a number of websites, including Expedia.co.uk, instructing them to stop alleged scraping.
Technology law expert Struan Robertson told OUT-LAW Radio recently that while companies could argue that their terms and conditions were broken, that may not stand up in court.
Robertson said that asserting a breach of database rights might be a more powerful argument.
Ryanair said that it objected to Bravofly's use of its flights as one of its products. "We make a really big effort to be Europe's cheapest low fares airline and then these companies top up our basic fare," said the spokesman.
"It's not like the customer is getting an extra service, so this is obviously not in our or our passengers' best interests," he said.