Italy's competitions watchdog has launched an inquiry into Ryanair's plans to charge passengers to take luggage on the plane.
Italian media are reporting that the Antitrust investigation highlights that the charge should be included in the ticket price.
They said that hand luggage is "an essential element of transport."
It comes after the airline's announcement last month that from November, passengers will be charged to take their luggage on board.
Ryanair said they are happy to cooperate with the investigation.
They said other airlines restrict the numbers of carry-on bags for safety reasons and that they "look forward" to explaining this to the Italian authority.