Berlin, January 2026. Berlin, January 2026. A 50 per cent reduction of CO₂ emissions per passenger kilometre – this is what airlines worldwide could theoretically achieve if they tapped into efficiency gains in three areas. This is the conclusion of a study to which atmosfair contributed data and calculation methodology. The study has now been published in the journal Communications Earth & Environment part of the Nature portfolio.

The team led by tourism professor Stefan Gössling examined three areas in which airlines can reduce kerosene consumption per passenger kilometre. The most important factor is the aircraft model. If airlines were to replace all older aircraft with the most modern and efficient models, such as the Boeing 787-9 or the Airbus A350, they could theoretically save 27 per cent in kerosene.

Aircraft model, layout, and load factor as adjusting factors

First- and business-class seats take up more space, meaning that CO₂ emissions per passenger are two to five times higher than in economy class. Completing the seating layout with the most efficient class could reduce emissions by around 26 per cent. Flight efficiency also depends on the load factor. If this could be increased from the current 80 per cent to 95 per cent, airlines could reduce fuel consumption by a further 16 per cent. Taken together, these measures would save more than 50 per cent of all emissions.

For this analysis, the study’s authors evaluated data from 27 million flights provided by atmosfair. The data cover a total of seven trillion passenger kilometres and include, among other details, aircraft models, engines, passenger capacities, and load factors. atmosfair combined this information with detailed technical aircraft models to calculate CO₂ emissions per passenger kilometre for each flight. The atmosfair Airline Index uses the same data and calculation methods.

According to the latest edition of the atmosfair Airline Index, airlines increased their CO₂ efficiency by 7.5 per cent between 2019 and 2024. This improvement is primarily due to the introduction of new aircraft that consume less kerosene.

The complete study is available here. An article in The Guardian also reports on this.