The white lines you see behind some airplanes don’t always disappear quickly. Under certain cold and humid conditions, these contrails can expand into clouds and trap heat in the atmosphere. Google estimates that they account for nearly one-third of aviation’s total climate impact.
Now, the company is taking its research from the lab to the skies over the Asia-Pacific region. Google has partnered with Cathay Pacific to test routes that avoid areas where persistent contrails are most likely to form during ultra-long-haul flights.
How AI Works to Avoid Contrails
The idea is simple, although making it work at scale requires quite a bit of technology: if an airplane slightly changes its altitude, it can pass through an atmospheric area that is less favorable to the formation of contrails that contribute to warming.
This doesn’t mean radically changing the route or affecting flight safety. These are small adjustments, similar to those crews make for operational reasons, always within established parameters.
The system combines several types of information:
- Artificial intelligence predictions about atmospheric conditions.
- Satellite images to identify contrails and analyze how they develop.
- Advanced weather data on temperature, humidity, and wind.
- Operational information to determine whether an altitude change is feasible.
Before takeoff, dispatch teams can study risk areas and prepare an alternative route. During the flight, Cathay Pacific receives updated predictions in the cockpit through the aircraft’s Wi-Fi connection and its Electronic Flight Folder, a digital tool that brings together operational information for pilots.
What’s the difference? The recommendation doesn’t stay inside a research model. It reaches the teams making real decisions, integrated into the workflows airlines already use.
More Than 80 Flights Show an Estimated 40% Reduction
The first phase of the trial included more than 100 flights across Cathay Pacific’s network. Of those, more than 80 followed routes designed to avoid conditions favorable to the formation of persistent contrails.
According to Google’s analysis of satellite images, those flights achieved an estimated reduction of approximately 40% in the warming impact associated with contrails. This figure doesn’t mean that all contrails were eliminated or that every flight achieved the same result. It is an estimate based on a comparison between the routes used and the conditions expected without intervention.
One of the corridors analyzed was the route between Hong Kong and Singapore. According to the trial results, the interventions on this route accounted for more than half of the estimated emissions reductions during the test.
That figure highlights something important: not all routes have the same potential. The usefulness of AI depends on accurately identifying the segments where a small altitude change can prevent a persistent contrail without creating disproportionate operational costs.
From Proof of Concept to Broader Operations
Google and Cathay Pacific will now expand the trial with a second phase of flights. They will also collaborate with Contrails.org, a nonprofit organization that works to develop scientific knowledge about contrail mitigation.
The expansion will make it possible to study how the approach works in different operational environments, including routes within Asia and transpacific flights. Each flight provides data on prediction accuracy, ease of use for crews, and the impact of altitude changes on operations.
This type of solution has an obvious advantage: it doesn’t require waiting for new airplanes or fuels to become available. In theory, it can be used with aircraft and fuel that are already available today, as long as reliable data exists and the adjustments are compatible with safety, air traffic, fuel consumption, and schedules.
AI can’t eliminate aviation’s climate impact on its own. Its value lies in helping identify small, concrete decisions that, repeated across thousands of flights, can make a significant difference.
The challenge now is to show that these predictions remain accurate across different regions and conditions. It will also be necessary to measure the results independently and understand when avoiding a contrail can offset the additional fuel consumption caused by a route or altitude change.
Aviation faces an enormous climate challenge, but not every solution has to begin with entirely new technology. Sometimes, a better weather prediction, a satellite image, and an operational decision made at the right time can turn a routine route into one with a lower impact.