Cathay Pacific and Google are expanding an artificial intelligence-powered trial designed to help aircraft avoid producing persistent contrails, moving the project into a larger second phase across Asian and trans-Pacific routes.
The expansion follows an initial operational trial in which more than 80 Cathay flights followed contrail-avoidance routes. Google said its satellite-imagery analysis estimated that those flights reduced the warming impact of contrails by roughly 40 percent. The figure is an estimate from the technology provider rather than an independently verified airline emissions result.
Google said in its September 7 announcement that Cathay is its first commercial airline partner in Asia for contrail avoidance on ultra-long-haul flights. Reuters reported that the companies described Cathay as the first airline globally to test the technology on flights of that length.
From forecasts to cockpit decisions
The system combines AI predictions, satellite imagery and weather information to identify cold, humid atmospheric zones where persistent contrails are more likely to form. Flight dispatchers and pilots can then plan small altitude changes intended to avoid those areas, subject to normal safety and operational requirements.
Cathay connects the forecasts to the flight deck through in-flight Wi-Fi and its proprietary Electronic Flight Folder. Google said this lets pilots receive updated information alongside the operational data they already use, without requiring a separate cockpit workflow.
The first phase began in late 2025 and targeted more than 100 flights across Cathay’s network. More than 80 ultimately followed an avoidance route. The Hong Kong–Singapore corridor was among those tested, and Google said interventions on that route accounted for more than half of the trial’s calculated climate-impact reduction.
The companies did not disclose how many flights will be included in the second phase, its expected duration, the precise routes involved or the fuel-use effects of the altitude changes. Those details will be important in assessing whether the approach can be applied consistently across a commercial network.
A non-CO2 aviation target
Contrails form when aircraft fly through sufficiently cold and humid air. While many disappear quickly, persistent trails can spread into cirrus-like clouds that trap heat. Google, citing the Intergovernmental Panel on Climate Change, said contrails account for roughly one-third of aviation’s total climate impact.
The project targets this non-CO2 effect with existing aircraft and fuel rather than waiting for new propulsion systems. Google’s earlier work with American Airlines provides a separate reference point. In results published in March, the company said its forecasts were integrated into flight-planning software for a trial involving 2,400 transatlantic flights. Flights that successfully followed avoidance plans recorded a 62 percent lower contrail-formation rate than a control group.
The two percentages measure different outcomes. The American Airlines work assessed contrail formation, while the Cathay estimate concerns warming impact, so they should not be treated as directly comparable performance figures.
Second phase tests regional scalability
The expanded Cathay program will cover operating environments across Asia and trans-Pacific routes. Google said it is also working with Contrails.org, a nonprofit applied-research organization focused on contrail management, to add the results to wider research on how forecasting and route adjustments can be used in airline operations.
The larger trial will test whether forecasts can remain useful across different weather systems, flight lengths and air-traffic conditions. It will also provide evidence on how readily airlines can incorporate avoidance recommendations into dispatch and cockpit decision-making.
For Cathay, the project represents a live operational use of predictive AI rather than a customer-facing feature or an internal productivity tool. For Google, it extends contrail research into the Asia-Pacific aviation market and onto ultra-long-haul services. The immediate significance rests on the scale and independently assessable results of the next phase, which the companies have not yet provided.
Featured image: Gabriela Natiello on Unsplash