State prosecutors and customs officials also searched several pilots' homes as part of the raids on Tuesday, Hans Peter Gandner, senior prosecutor in the state of Rhineland-Palatinate, told AFP.
The searches were part of an investigation into two British temp agencies that supply self-employed pilots to Ryanair and not directed against the airline itself, Gandner said.
The temp agencies stand accused of tax evasion and withholding salaries, while several pilots are suspected of being complicit in the scheme and of fraud against the social security system.