Google and American Airlines Use AI to Cut Contrail Formation by 62%
When aircraft pass through cold, humid airspace, exhaust particles can condense into clouds of ice crystals. Some persist for hours and trap heat emitted from Earth's surface. Since 2023, Google Research has worked with American Airlines and Breakthrough Energy to train AI using satellite, weather and flight data. Contrails account for more than one-third of aviation's warming impact, making avoidance of contrail-forming areas a potentially low-cost climate measure.
Google released the results on March 19, 2026. From January to May 2025, American Airlines integrated AI forecasts into the Flightkeys system and tested them on 2,400 transatlantic flights between the United States and Europe. The 112 flights that actually used avoidance routes recorded 62% less contrail formation than the control group and about a 69% reduction in warming impact. Fleetwide fuel consumption was estimated to increase by 0.3%, while the climate benefit was 20 times the warming impact of the additional fuel. The cost of deployment was not disclosed.
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The history behind this eventGoogle, UK Launch AI Trial to Cut Aircraft Contrails
Aircraft contrails form when jets pass through cold, humid air and can trap heat that would otherwise escape into space. Their warming effect is a significant part of aviation’s climate footprint beyond carbon dioxide emissions. Operation Blue Skies brings together the UK government, Google and partner organizations to test whether artificial intelligence can help aircraft avoid the atmospheric zones most likely to produce persistent, heat-trapping clouds.
The first-of-its-kind trial will combine weather forecasts and satellite observations to identify contrail-forming regions over North Atlantic routes. Air traffic controllers will then make small adjustments to aircraft altitude to steer flights away from the predicted warming zones. The project aims to show that targeted rerouting can substantially reduce aviation’s climate impact while adding very little fuel use, and assess whether the approach can be incorporated into routine flight operations.
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