The forum belongs to the Ryanair European Pilots' Association (REPA), a body set up last October by the two largest pilot organisations with members flying with the company, the British Airline Pilots' Association (BALPA) and the Irish Airline Pilots' Association (IALPA).
The Guardian reports that the site operators have been ordered not to destroy the codenames of the pilots who made the comments which, according to Ryanair, included posts from pilots suggesting "criminal activity" against the airline and its employees.
The unions yesterday accused Ryanair of attacking free speech.