How are Cathay Pacific and Google using AI, satellite imagery, weather intelligence, live in flight forecasts, and minor altitude adjustments to trial persistent contrail avoidance—including on ultra long haul and Hong Kong–Singapore flights—and what early results, expansion plan

Cathay Pacific is using Google’s AI contrail forecasts to identify narrow, ice-supersaturated air layers where exhaust trails can persist and warm the climate, then planning or requesting small cruise-altitude changes to avoid them. The appeal is an operational intervention that can work with today’s aircraft and fuel, rather than waiting for new fleets or large-scale sustainable-aviation-fuel (SAF) supply. 26

• How the system works: Google combines flight data, large-scale weather data and satellite imagery with computer vision to forecast contrail-prone zones and their likely climate effect up to 48 hours ahead. Its forecasting combines an ML model for contrail likelihood with a physics-based model for warming impact. 26

• What Cathay changes: Rather than rerouting an entire journey, crews trial small vertical deviations—moving above or below thin humid layers at cruise altitude—to avoid the conditions that make contrails persistent. Persistent contrails are the concern because they can spread into cirrus-like cloud and trap outgoing heat. 85

• Early Cathay results: In a first phase begun in late 2025 and covering more than 80 flights, Cathay and Google estimate that following avoidance routes cut contrail warming impact by about 40%. That is an early company estimate, not yet a definitive independently replicated climate result. 84

• Routes and expansion: Cathay is Google’s first commercial airline partner in Asia. The next phase, with nonprofit Contrails.org, is intended to extend work to ultra-long-haul Asian and transpacific operations; reports describe the initial operational work as including Hong Kong–Singapore flying. 810

• Why Asia-Pacific matters: It brings contrail research and operational validation into the world’s fastest-growing aviation region, where meteorology, satellite coverage, traffic patterns and air-traffic constraints differ from prior U.S. and North Atlantic studies. It therefore tests whether models trained and validated elsewhere transfer reliably to tropical and long-haul Asian operations. 83

• Climate significance: Estimates vary by metric and time horizon, but persistent contrails are widely assessed as a major—often roughly one-third or more—component of aviation’s total warming impact. That makes targeted avoidance potentially important even though it does not reduce the CO2 emitted by burning jet fuel. A commercial-flight study independently found 63.6% fewer detectable contrails in its avoidance group than in its control group. 1

• Cost and practicality advantage: Small, selective altitude changes require forecasting, flight-planning and air-traffic coordination—not replacement aircraft, new propulsion systems or an airport fuel-supply overhaul. Modeling reviewed by ICAO indicates that meaningful contrail reductions can be achieved with modest fuel penalties when only the most climate-damaging contrail opportunities are targeted. 7

• Relative to SAF and fleet renewal: SAF and more efficient aircraft remain necessary for long-lived CO2 reductions. Contrail avoidance is complementary: it can address a near-term non-CO2 warming effect using the existing fleet, while SAF availability, cost, lifecycle emissions and fleet turnover remain constraints. SAF may reduce soot and hence contrail formation propensity, but it does not make contrails disappear or substitute for accurate avoidance forecasts. 12

The key caveat is operational scale: the forecast must be accurate, altitude changes must be approved and safe, and any extra fuel burn must be smaller than the warming avoided. The 40% Cathay figure should therefore be treated as promising trial evidence rather than a settled fleet-wide outcome. 87