A new study has identified the top 10 most polluting airlines in Europe, calling for urgent reforms to the carbon market in order to effectively address aviation’s environmental impact.
In 2024, emissions from flights within Europe surged to nearly pre-COVID levels, with 8.4 million flights departing from European airports, releasing 187.6 million tonnes (Mt) of CO₂, according to Transport & Environment (T&E). This is just 96% of 2019 flight numbers and 98% of 2019 emissions.
However, T&E claims that due to loopholes in aviation’s carbon market rules, airlines were exempt from paying for 70% of the pollution they generated.
“Aviation emissions are spiralling out of control. To add insult to injury, the sector continues to dodge the true cost of its pollution, making a mockery of airlines’ pledges to build back greener after COVID,” said Krisztina Hencz, aviation policy manager at T&E. “If Europe continues down this path, ‘green’ aviation will remain a figment of people’s imaginations.”
T&E calls for an overhaul of the EU carbon markets during an upcoming review next year, aiming to close the existing loopholes and ensure airlines take full responsibility for their emissions. According to the study, just ten airlines accounted for 40% of all European aviation emissions in 2024, with the worst offenders being Ryanair (16.2 Mt CO₂), Lufthansa (10 Mt CO₂), and British Airways (8.9 Mt CO₂). These emissions represent a 9%, 6%, and 3% increase over the previous year, respectively.
Air France follows closely behind, emitting 8.2 Mt CO₂, though this marks a slight 1% reduction from the previous year. The rest of the top 10 includes easyJet, Emirates, KLM, Wizz Air, Iberia—which saw the highest year-on-year increase of 10%—and United Airlines.
The study also highlights the growing dominance of low-cost carriers in Europe’s aviation market, including routes outside the European Union traditionally controlled by legacy carriers like Lufthansa and Air France. Currently, airlines are only required to pay for emissions from flights within the European Economic Area (EEA), the UK, and Switzerland, but long-haul flights—typically the most polluting—are not subject to these regulations.
The most carbon-intensive routes departing from Europe in 2024 were all intercontinental, with the London-New York route at the top, emitting over 1.4 Mt of CO₂. Other highly polluting routes included London to Dubai (1.2 Mt CO₂) and London to Singapore (1.1 Mt CO₂). The first EU-originating route to make the list was Frankfurt to Shanghai, which released 0.8 Mt CO₂.
The Barcelona-London route, which is covered under the EU Emissions Trading System (ETS), ranked 135th on the list, with only 0.15 Mt CO₂ emitted. This indicates that no airline had to pay for emissions on Europe’s most polluting routes, a “fundamental flaw” according to T&E, who argue this represents a missed opportunity for the carbon market to address aviation’s environmental impact.
