American Airlines and Google have achieved a 62% reduction in contrail formation on transatlantic flights by leveraging artificial intelligence to optimize flight paths, a new study reveals. The collaboration, which included flight planning provider Flightkeys and research group Contrails.org, demonstrates a potentially scalable and cost-effective approach to mitigating the climate impact of aviation.
Contrails, the visible condensation trails left by aircraft, are formed when water vapor from engine exhaust freezes in the cold, humid air of the upper atmosphere. Although seemingly benign, these ice crystal clouds can trap heat and contribute significantly to global warming. Some studies suggest contrails may have a warming effect comparable to that of carbon dioxide emissions from aviation, making them a crucial target for climate mitigation efforts, according to Contrails.org.
Google’s AI-powered system analyzes vast datasets of satellite imagery, weather patterns, and flight paths to predict where contrails are most likely to form. This information is then integrated into American Airlines’ flight planning systems, allowing dispatchers to suggest minor adjustments to altitude or routing to avoid these areas. The adjustments often require only minimal deviation from the original flight plan.
Initial trials in 2023, involving 70 flights, showed a 54% reduction in contrail formation, with fuel impact as low as 0.3%. The recent, expanded trial, conducted between January 15 and May 13, 2025, encompassed 2,400 American Airlines transatlantic flights. Researchers found that flights following the AI-recommended paths reduced contrail formation by 62% compared to a control group, with up to a 69% reduction in associated warming impact, and no statistically significant difference in fuel burn.
The aviation industry currently accounts for approximately 2.5% of human-made global CO2 emissions, according to the International Air Transport Association. Still, the industry’s overall climate impact extends beyond CO2 to include short-lived climate pollutants (SLCPs) such as contrails, nitrogen oxides, and black carbon aerosols. Addressing these non-CO2 emissions is increasingly recognized as critical for near-term climate action.
“Governments and industry are right to invest in clean aviation fuels, which are essential to the long-term sustainability of aviation,” said Dan Rutherford, Senior Director of Research for the International Council on Clean Transportation (ICCT), in a statement accompanying a recent ICCT study on SLCP controls. “But small changes in how aircraft are flown to cut contrails may protect our climate even more in the near and medium-term.”
Scaling this technology globally presents challenges, including integration with existing flight planning systems, adoption by multiple airlines, and international airspace coordination. Google has indicated plans to expand the technology to other flight-planning platforms, aiming to embed contrail forecasting across the industry.
With aviation facing growing pressure to reduce its environmental footprint and sustainable aviation fuel supply remaining limited, contrail avoidance offers a readily deployable solution. The approach provides airlines with an immediate operational advantage by leveraging data and AI to reduce their climate impact while awaiting advancements in aircraft technology and sustainable fuel production.
Leave a Reply