The International Council on Clean Transportation (ICCT) released a new analysis of commercial aircraft fuel efficiency from 1960 to 2024, showing that improvements have stagnated since international CO₂ standards took effect in 2020.

The study comes as policymakers prepare to gather in Montreal on 17 February to update international aviation standards in support of the sector’s 2050 net-zero cO₂ goal.

The new working paper, “Fuel burn of new commercial jet aircraft: 1960 to 2024,” finds that the primary cause of the efficiency plateau is a sharp decline in the certification of new, more efficient aircraft types. New type certifications have fallen from a peak of six per year in the late 1990s to less than one per year after 2020. Beyond Boeing’s 777X, manufacturers have not committed to developing additional new aircraft types before 2035.

This research demonstrates that ICAO’s 2028 CO₂ standard lags state-of-the-art technology by about a decade. With improvements in new aircraft expected to contribute about one-sixth of all emission reductions under aviation’s net-zero target, stronger standards are crucial.

—Nikita Pavlenko, ICCT’s Aviation Program Director

The analysis concludes that a CO₂ standard 15% more stringent than the current requirement is needed to promote the development of new, more efficient aircraft types. This recommendation comes as ICAO’s Committee on Aviation Environmental Protection prepares to meet in Montreal to consider updates to the international CO₂ standard.