This question refers to the so-called 'one bag rule' imposed by some airlines whereby they restrict to one, the number of bags that can be brought into the cabin of an aircraft by passengers.
This is currently a matter of individual airline policy and is not regulated under EU law. Under proposals published by the European Commission to amend Regulations 261/2004 and 2027/97 concerning air passengers' rights, the Commission has tabled a new Article to Regulation (EC) No. 2027/97 that will make it more transparent what charges will apply for passengers who wish to bring baggage into the cabin of an aircraft and I welcome this proposed change. However, it will remain a matter for airlines to decide on the fares and conditions of carriage for passengers and their baggage. I understand the concerns of retailers at airports.
However, the Commission has not proposed regulating in this area as pricing and conditions of carriage are commercial freedoms for airlines. The greater transparency provisions proposed by the Commission will ensure that passengers are better informed about what restrictions apply as under these proposals, airlines will have to make these known to passengers both on booking and at check-in.