Hong Kong, September 7 : Cathay Pacific and Google will expand trials of an artificial intelligence-based system aimed at reducing the climate impact of aircraft contrails after early testing showed an estimated 40 per cent reduction in contrail-related warming, according to a joint release issued on Monday.
An operational trial that began in late 2025 targeted more than 100 flights across Cathay Pacific's network, with more than 80 flights following contrail-avoidance routes.
“Google estimates that these flights achieved roughly 40% reduction in the warming impact of contrails,” the companies said in the release. 
Following the initial trial, Cathay Pacific and Google are now undertaking a larger second phase of flight trials across the airline's Asia and transpacific network to gather more real-world operational data.
The companies said the initial trial produced encouraging results on individual flights, but cautioned that further research was required to assess the benefits of applying contrail-avoidance measures across airlines and airspaces. 
Cathay Pacific is Google's first commercial airline partner in the Asia-Pacific region to trial its AI-powered contrail mitigation technology and the first airline globally to test contrail avoidance on ultra-long-haul flights, according to the release. 
Contrails, or condensation trails, are the thin white lines that sometimes form behind aircraft when they fly through cold and humid conditions at high altitude. While many disappear quickly, some persist and spread into larger cloud formations that can trap heat in the atmosphere.
The release cited previous research suggesting that persistent contrails could account for around one-third of aviation's total climate impact. 
Google's contrail mitigation system combines AI-based predictive models, satellite imagery and weather intelligence to forecast areas where contrails are likely to form. The information allows flight dispatchers and pilots to make altitude adjustments to avoid such areas.
Cathay Pacific uses the forecasts through its Electronic Flight Folder system, which provides pilots with Google contrail forecasts alongside real-time operational information. 
Lawrence Fong, Director Digital and IT at Cathay, said, “Aviation needs solutions to address climate change, and AI is accelerating that progress.”
“This partnership combines Cathay’s operational expertise with Google’s world-class AI capabilities to tackle complex sustainability challenges at scale,” he added. 
Google Hong Kong Managing Director and General Manager Michael Yue said the partnership was researching how predictive AI could be deployed in live operations “to help address the climate impact of contrails with today’s aircraft and today’s fuel.” 
The companies said the expanded trials are aimed at creating a broader operational data set that could improve scientific understanding of contrail avoidance and help inform future industry practices.