An Austrian court ruled that Austrian Airlines AG misled the public last year when it published ads offering CO2-neutral flights that used 100% sustainable aviation fuel (SAF), between Vienna and Venice.

The greenwashing case was brought by Austria’s Association for Consumer Information (VKI). The ruling ordered the airline to publish information about the case on its social media.

Sustainable aviation fuel is seen as one of the key tools to help decarbonize the aviation industry, which currently accounts for 2-3% of global greenhouse gas (GHG) emissions. SAF is generally produced from sustainable resources, like waste oils and agricultural residues, providing substantial emissions reductions relative to current fossil-based jet fuels. Currently, however, SAF represents only around 0.1% of the fuel used in aviation globally today according to the International Energy Agency.

According to the ruling, Austrian Airlines gave a false impression through advertising statements such as “Fly CO2-neutral with us,” or “100% SAF.”  Marketed for flights between Vienna and Venice, the campaign allowed consumers to pay a surcharge in excess of 50% of the ticket price for the CO2-neutral option, with the airline purchasing SAF to be added to future flights.

In its complaint, VKI noted that the maximum proportion of SAF was actually 5%, and that it is not currently possible to operate 100% SAF flights.

VKI lawyer Barbara Bauer said:

“In principle, we welcome all corporate efforts that serve to protect the environment. But promoting flights as CO2-neutral when this is not technically possible and it cannot even be ensured that sustainable aviation fuel is used in the specific flight is definitely going too far. The fact that consumers have to pay a hefty surcharge for this dubious service is a special treat of this marketing strategy.”

The case marked the latest in a series of greenwashing challenges for airlines. Austrian Airlines is a subsidiary of Lufthansa which was also found to have misled consumers through greenwashing earlier this year. UK regulator Advertising Standards Authority said that Lufthansa’s ads inaccurately insinuated that the airline “had taken significant mitigating steps to ensure that the net environmental impact of their business was not harmful.”

Additionally, BEUC, the European Consumer Organization, has filed a complaint against 17 EU airlines, including Austrian, for misleading climate-related claims. This includes claims that customers can pay extra credits to offset the CO2 emissions of the flight; charging flyers more and claiming that the extra cost contributes to the development of SAFs; or implying that air travel can be sustainable.