Several budget airlines including Ryanair have been hit with fines of €150m by Spain for policies that include 'unfair' hand luggage pricing.
The Spanish Ministry of Consumer Affairs said the fine against Ryanair, Vueling, Volotea and Easyjet was for 'abusive practices'.
It is one of the first times that a 2014 European Court of Justice ruling, stipulating hand luggage cannot be subject to additional charges as long it meets reasonable weight and size requirements, is being applied.
The Spanish airline association Asociación de Líneas Aéreas (ALA) has rejected suggestions of banning extra payments for cabin baggage.
"It will harm consumers by removing the option for passengers to hire exactly what they need," the body said.
"As a result, the 50 million or so passengers who currently do not carry cabin luggage on board and only travel with hand luggage under the seat would not be able to benefit from paying only for essential services, forcing them to purchase services they do not use."
The tailfin of Ryanair Boeing 737-800 aircraftTravel Extra editor Eoghan Corry told The Anton Savage Show Ryanair will not take this lightly.
"Ryanair are being told you can't charge to put families sitting together and you can't charge for cabin bags," he said.
"They faced this resistance right across Europe from the very beginning; they're feisty, they're not going to lie down - they're going to appeal this."
Mr Corry said he believes all four carriers will "get together and appeal this".
"The argument... is that if you want to sit [together] you pay a few euro extra," he said.
"If you don't you get a cheaper flight - that's the argument.
"It's a consumer organisation that are penalising them and it's going to probably run on for a few more years.
"Spain is a very important market for Ryanair, they're not going to walk away from it," he added.
EU standardisation
Agustin Reyna of the European Consumer Organisation (BEUC) said there needs to be harmonised policies across the European Union.
"This is a strong and welcome signal from the Spanish authorities because unfair policies from airlines about carry-on hand luggage need to stop," he said.
"Too often, consumers arrive at the airport only to be told by the airline that they have to pay extra to have hand luggage or because their bags don't conform to the airline’s rules on size.
"What we now need are EU-wide standards for hand luggage policies to harmonise what airlines require of consumers and to smoothen air passengers’ experience," he added.
