Low-cost airlines are asking the European Union to request airlines to apply a certain share of sustainable fuel to all flights but not only short-haul ones.

The European Commission is drawing a plan for carriers to use a minimum share of sustainable aviation fuels (SAF) to restrain the aviation industry’s CO2 emissions impacting the planet and facilitating global warming. Several carriers, such as Easyjet, Ryanair, Wizz Air, Jet2, and environmental groups asking the European Commission to make SAF quotas applicable to long-haul trips as well, in addition to flights inside Europe.

“Excluding long-haul flights from the SAFs mandate would mean the very area of our sector that most needs to decarbonise would not be covered at all by this legislation,” said the letter to the EU’s climate and transport policy chiefs.

The signatories referred to the air traffic management group’s, Eurocontrol’s, data, which reveals 6% of flights from European airports that flew over 4,000 km accounted for half of the total CO2 emission.

“There is no logic in excluding long-haul flights from SAF usage obligations as this is their only possible way to decarbonise,” Ryanair CEO Michael O’Leary said in a statement.

Nevertheless, SAFs are only a short-term solution since, closer to the 2030s, aviation will be seeking to deploy new technologies like hydrogen fuels.