When people think about aviation emissions, they usually think about the carbon dioxide coming from aircraft engines.

But there is another part of flying that is attracting increasing attention from climate researchers: the white trails airplanes leave behind in the sky.

These trails, called contrails, form when aircraft fly through very cold, humid air. Some disappear quickly. Others can persist and spread into thin cloud-like formations that trap heat in the atmosphere.

Now, Google and Cathay Pacific are taking their efforts to reduce this effect into a larger real-world trial across the Asia-Pacific region. Their approach uses artificial intelligence, satellite imagery and weather data to help identify areas where aircraft are more likely to create warming contrails.

What Makes Contrails a Climate Problem?

A contrail may look harmless, but under the right atmospheric conditions it can remain for hours and develop into a wider ice cloud.

These clouds can affect how much heat escapes from Earth. According to Google, the climate effect of contrails accounts for roughly one-third of aviation’s total climate impact when their warming effects are considered alongside aviation’s CO₂ emissions.

That makes contrails an unusual climate problem because airlines do not necessarily need to build completely different aircraft to address it.

In some cases, they may only need to change where an aircraft flies.

How Can AI Help?

The challenge is knowing exactly where contrails are likely to form.

Atmospheric conditions can change considerably with altitude and location. Google’s system combines weather information, satellite imagery and AI predictions to identify areas where an aircraft could create a persistent contrail.

Flight planners can then look for a slightly different altitude or route that avoids those conditions.

The changes can be relatively small. Pilots already make altitude adjustments for operational reasons, so the goal is to provide flight crews with useful information early enough to incorporate contrail avoidance into normal flight planning.

Cathay Pacific is connecting these forecasts to its flight operations through in-flight connectivity and its Electronic Flight Folder, allowing pilots and flight teams to receive the information alongside other operational data.

The Early Results Are Interesting

Google and Cathay Pacific began their initial operational trials in late 2025.

More than 100 flights were targeted, and more than 80 eventually followed contrail-avoidance routes. Google’s analysis estimated that these flights reduced the warming impact of their contrails by around 40%.

That figure comes from Google’s analysis of the trial, so it should not be treated as proof that every flight can achieve the same reduction.

The companies now want much more real-world data.

The next phase will expand the trials across Cathay Pacific’s network and include ultra-long-haul routes in Asia and across the Pacific. The companies are also working with Contrails.org to strengthen the scientific research behind the approach.

Why This Approach Is Different

The interesting part is that the solution does not depend on replacing jet fuel or waiting for a new generation of aircraft.

It works with today’s aircraft.

If the technology proves reliable, airlines could potentially reduce some climate impact through small operational changes rather than major hardware modifications.

That gives contrail avoidance an important place alongside other aviation solutions such as sustainable aviation fuel, more efficient aircraft, improved air traffic management and electrification research.

But it is not a replacement for those measures.

Airlines still need to reduce carbon dioxide emissions. Avoiding contrails addresses a different part of aviation’s climate footprint.

There Are Still Questions to Answer

The technology remains under real-world testing.

Researchers need to understand how accurately AI can predict contrail formation across different regions, weather conditions and flight routes. Airlines also need to determine whether avoiding a contrail creates additional fuel consumption or operational complications.

Safety remains the first constraint.

Any altitude or routing adjustment has to fit within established aviation procedures and must not compromise normal flight operations. Google says the planned changes are designed to remain within existing safety parameters.

There is also a scientific challenge. Contrails do not behave exactly the same way everywhere, which makes more regional testing important.

That is one reason the Asia-Pacific trial matters.

A Bigger Idea Behind the Experiment

The technology points toward an interesting shift in how we think about climate solutions.

Sometimes reducing environmental impact does not require creating something entirely new.

It can mean using better information to make better decisions with the infrastructure we already have.

An aircraft may still fly the same journey, use the same engine and carry the same passengers. The difference could simply be choosing a slightly different altitude at the right moment.

If AI can reliably identify those opportunities, a small operational decision could potentially prevent a much larger climate effect.

The Cathay Pacific trial is still an experiment, not a finished solution. But it shows how artificial intelligence is moving beyond conventional digital applications and into the physical systems that shape the planet’s climate footprint.

And in this case, the next climate intervention may not happen on the ground.

It could happen several kilometres above it.