German airline Lufthansa has applied for an injunction against Ryanair to stop it publishing information it says is economical with the truth.
Lufthansa says adverts for cheap flights are misleading because they highlight single fares, and the flights are to provincial airports.
But Ryanair claims Lufthansa is just 'whinging' because it can't compete.
A spokesman at Cologne regional court confirmed Lufthansa wants to stop Ryanair adverts for a 49 Mark (just under £20) ticket from Germany to London Stansted. It says the advert only shows the full price of 109 Marks (£45) - for a return trip including taxes - in small print at the bottom.
A further complaint was registered that Ryanair was confusing visitors to its website who wanted to travel to Frankfurt or Hamburg. Lufthansa said that by using the names of those cities, Ryanair was hiding the fact that the real airports used were smaller ones at Hahn in Hunsrueck near Frankfurt, and Luebeck rather than Hamburg.
Ryanair press officer Mr Enda O'Toole claimed Lufthansa were "just whinging because they can't compete with Ryanair's low fares."
The judge in Cologne is expected to deliver a verdict on October 23rd.
AFP