Cathay Pacific and Google are expanding trials of technology designed to reduce the climate impact of aircraft condensation trails. Cathay is Google’s first commercial airline partner in Asia-Pacific and the first carrier to test contrail avoidance on ultra-long-haul flights.
Google’s system combines artificial intelligence, satellite observations and weather data to predict areas where persistent contrails are likely to form. These forecasts are supplied to Cathay’s dispatchers and pilots, who can make minor altitude adjustments to avoid the affected zones, subject to operational and air-traffic-control requirements.
An initial trial began in late 2025 and covered more than 100 flights, over 80 of which followed contrail-avoidance routings. Google estimates that the measures reduced the warming effect of contrails on those flights by approximately 40%. The Hong Kong–Singapore route produced more than half of the trial’s estimated climate benefit.
Persistent contrails can spread into cloud formations that trap heat and may account for around one-third of aviation’s overall climate impact, although their effects remain subject to scientific uncertainty. Cathay said contrail mitigation would complement—rather than replace—efforts to cut CO? emissions through newer aircraft, operational efficiencies and sustainable aviation fuel.
A larger second phase will now collect data across Cathay’s Asian and transpacific network, with nonprofit research initiative Contrails.org also participating. The partners said further evidence is needed to establish whether contrail avoidance can be applied safely and effectively across different airlines, routes and airspaces.