An advert promoting Wizz Air as "one of the greenest choices in air travel" has been prohibited by the advertising regulator for being misleading to customers. Initially spotted in June, a Google ad paid for by the budget airline prompted customers with the message "fly Wizz Air – one of the greenest choices in air travel."

On Wednesday, the Advertising Standards Authority (ASA) decided that this advertisement “must not appear again in the form investigated” due to its failure to transparently present the basis for this claim.

The ruling hinges on Wizz's inability to supply sufficient information that would enable consumers to validly compare it to other airlines' emissions. Going forward, Wizz Air is required to ensure any comparative environmental claims clearly detail the basis and avoid giving a "misleading impression" regarding the flights' environmental impact, the ASA stated.

The Hungarian airline stood by the ad and said it was satisfied that the regulator recognised the ad's reliance on "credible emissions results, which are the lowest of any airline globally."

A company spokesperson defended that Wizz Air boasts "the lowest carbon emissions per passenger kilometre of any other airline" and highlighted that it is "one of the few airline actively investing in the production of sustainable aviation fuels (SAF)," which is considered essential in reducing the carbon footprint of flying.

Wizz has made this claim before, basing it on the deployment of the lighter A321neo aircraft to diminish per-flight fuel usage, as reported by .

A spokesperson stated: "While it’s important to hold airlines accountable for their communications, equally this should be counterbalanced with the recognition of significant investments made to decarbonise the industry,"

However, the ASA's decision will likely raise further questions about the environmental claims made by some airlines, many of which are seeing substantial profits following a surge in passenger demand post-Covid. Virgin Atlantic was reprimanded by the advertising regulator in August for misleading customers about its landmark 100 per cent SAF-powered flight from London to New York in November last year.

Airlines have promoted SAF as crucial to achieving climate targets without reducing flights, but a massive increase in global production is required and the biofuel is still decades away from widespread use. Despite cancellations linked to the Middle East conflict, Wizz Air transported a record 62m passengers in 2023 and reported profits exceeding £300m.

Like this story? Why not sign up here for free to get the latest business news straight to your inbox.