Overview
- Published in Communications Earth & Environment, the study examined more than 27 million flights in 2023 across 26,000 city pairs carrying nearly 3.5 billion passengers, with an average intensity of 84.4 gCO2 per passenger‑km.
- Researchers outline three levers—flying the most fuel‑efficient aircraft, switching to all‑economy layouts, raising load factors toward 95%—and estimate a 50–75% cut in emissions if applied systemwide.
- The authors say airlines could trim emissions by about 11% immediately by redeploying the most efficient aircraft already in their fleets on existing routes.
- Efficiency varied sharply by geography and airport, with higher intensities frequently recorded from parts of the US, Australia, Africa, and the Middle East, and lower intensities in Brazil, India, and Southeast Asia; Atlanta and New York ranked among the least efficient, Abu Dhabi and Madrid among the most efficient.
- Industry and regulators offer caveats: IATA cites a backlog exceeding 5,000 aircraft orders and emphasizes SAF and airspace modernization, while ICAO estimates operational improvements deliver only 4–11% of needed cuts.