European Consumer Organisation BEUC is leading a complaint to the European Commission claiming the carriers have breached EU rules on unfair commercial practices by making false claims about their green credentials.

BEUC said: “We are calling for a Europe-wide investigation into the issue and for the concerned airlines – and the entire sector – to stop making claims that give consumers the impression that flying is sustainable. 

“This is simply untrue, as flying is not sustainable and is not bound to become so in the near future. Where airlines have proposed consumers to pay extra ‘green’ fees based on such misleading claims, CPC authorities should request airlines to reimburse their customers.”

As well as Wizz, Ryanair Air France and KLM, the submission also targets the Lufthansa Group, Finnair, Norwegian, TAP Air Portugal, SAS, Air Baltic, Vueling, Air Dolomiti and Volotea.

BEUC said several greenwashing examples had been identified. Among them were claims that paying extra credits can “offset”, “neutralise”, or “compensate” CO2 emissions of a flight, which it said was “factually incorrect”.

“The climate benefits of offsetting activities are highly uncertain, while the harm caused by the CO2 emissions from air travel is certain,” it said.

BEUC also said airlines were misleading consumers by charging more to contribute to the development of Sustainable Aviation Fuels.

It said: “Such fuels are not market-ready, and recently adopted EU legislation sets very low targets for how much they should represent in aircrafts’ fuel mix. This means that until SAFs are massively available – beyond the end of the 2030s – they will at best only represent a minor share in planes’ kerosene tanks.” 

It added: “Implying that air travel can be “sustainable”, “responsible” and “green” is deceptive. None of the strategies deployed by the aviation sector are currently able to prevent greenhouse gas emissions. 

“It is important to stop these claims, as with air traffic set to increase, emissions will keep rising for years to come.”

Ursula Pachl, BEUC’s deputy director general, said: “When it is crystal-clear that air travel causes a significant and increasing share of greenhouse gas emissions, it beggars belief that airlines freely lure consumers with climate-friendly messaging such as “CO2-compensated” or “CO2-neutral”. 

“We urge authorities to take the matter into their hands and crack down on this greenwashing practice [that is] seriously misleading consumers.”

BEUC’s action does not have UK involvement, but Rory Boland, Which? Travel editor, said: “It’s utterly cynical for any airline to use unfounded green claims to boost sales. Consumers must be given accurate information at the time of booking so that they can make an informed decision before purchasing a ticket."

Industry body Airlines for Europe said it had “always” met passengers’ demands for high transparency but added: "We continuously learn about and improve our sustainability communication, carefully reviewing all messaging to enhance transparency. We are dedicated to assessing what can be improved and made even more transparent to effectively communicate our efforts and progress in sustainability."