The solution mitigates the warming effects of contrails by adjusting flight paths
Published Mon, Sep 7, 2026 · 05:07 PM
ALPHABET’S Google and Cathay Pacific Airways are putting artificial intelligence to work on one of the aviation industry’s most visible but least-addressed climate problems.
Contrails, the crisp white condensation plumes that often trail aircraft flying at high altitudes, are composed of frozen water vapour attached to engine exhaust particles.
While they mar blue skies and are the basis of conspiracy theories, their main risk is as an environmental hazard by trapping heat – just like naturally forming cirrus clouds.
Contrails are responsible for roughly one-third of aviation’s total climate impact, according to Google. But this effect can be reduced significantly based on early-stage operational trials conducted in late 2025 on several dozen Cathay routes using Google’s AI algorithms, the companies said on Monday (Sep 7).
A pilot project achieved a 40 per cent decline in the warming effect of contrails by simply prompting pilots to avoid atmospheric sweet spots where they tend to form.
Google’s solution, currently offered free of charge, combines predictive AI models, satellite imagery and weather data to identify contrail-conducive zones.
The information is then turned into something operationally useful: suggested altitude adjustments that allow flight planners and crews to navigate away from certain areas, much as aircraft routinely alter course or altitude to avoid pockets of turbulence.
Cathay is Google’s first airline partner in the Asia-Pacific to try out its AI-powered contrail mitigation technology, and the first to test contrail avoidance globally on ultra-long-haul flights. Google has worked with American Airlines on similar trials.
Cathay’s director of digital and information technology Lawrence Wong said that the partnership “brings together the best of technology and operational expertise, demonstrating how data, AI and innovation can be applied to solve real-world challenges at scale”.
For carriers seeking to curb their climate impact, the research has opened up a new frontier beyond improvements in aircraft efficiency and sustainable fuel experimentation.
“This climate lever is available to the aviation industry for their existing aircraft fleet and any type of fuel they use currently,” said Kemal Armada, Google’s Zurich-based contrail research lead project manager, in an interview. “It’s extremely low-cost and effective.”
A modest change in altitude, made at the right moment and in the right atmospheric conditions, could prevent cloud formation that might otherwise persist for hours, he added.
But he noted challenges to wider-scale implementation in the airline industry include regulatory requirements, airspace restrictions and airlines’ own cost-focused and safety-focused operational considerations.
A second, expanded phase of the trial will start this week across Hong Kong-based Cathay’s intra-Asia, transpacific and polar networks, the companies said.
The goal is to obtain an even larger operational data set to get a clearer picture of where contrail avoidance works – and where it doesn’t – on ultra-long-haul flights. BLOOMBERG
