Operation Blue Skies Takes Off: Landmark Oceanic Airspace Trial to Test AI-Driven Contrail Avoidance

A UK-based consortium comprising Google, the UK Department for Transport, the Met Office, NATS, Contrails.org, Imperial College London, and the University of Cambridge has launched Operation Blue Skies, backed by the UK Government as the world’s first oceanic airspace-scale trial, aimed at reducing the climate impact of aviation contrails.

Operation Blue Skies is a £5 million, 30-month programme, partly funded by £2.65 million from the UK Government’s Department for Transport. It comprises two operational trials conducted during the winter months, across NATS-controlled Shanwick oceanic airspace, the eastern half of the North Atlantic corridor. The programme will evaluate the operational feasibility and environmental benefits of adjusting commercial flights’ altitude to avoid the atmospheric conditions that contribute to the formation of persistent, warming contrails.

Atmospheric modeling shows that the Shanwick airspace accounts for approximately 5% of global contrail warming (1) and a significant fraction of this warming is concentrated in the winter season between November and February. Operation Blue Skies is designed to target this specific high-impact window by using AI models to identify where and when interventions have the greatest potential to reduce contrail-related climate impact.

The trials will focus on minor altitude adjustments within standard flight operations, coordinated through established and standard Air Traffic Control (ATC) communication channels. Trial manoeuvres will take place primarily during winter testing windows in 2026-2027 and 2027-2028, with approximately 20 to 40 test days per winter. Testing will be conducted during periods of lower air traffic.

This trial sits alongside major UK Government investments in innovative aviation decarbonisation projects, including £219 million to boost homegrown green fuel production to cut emissions from flying whilst boosting growth and creating green jobs.

Shanwick airspace.

Keir Mather, UK Government Minister for Aviation, Maritime and Freight, said:

“We’re partnering with Google to back British experts and innovators to find practical ways to make flying cleaner. This is a world-first, and it’s British ingenuity leading the way. By testing small tweaks to flight paths over the Atlantic, we can cut the vapour trails left behind by planes.

From £219 million for home-grown sustainable fuel to zero-emission aircraft, we’re backing innovation to make UK aviation cleaner, support thousands of skilled jobs, and drive growth in the sector.”

Driving Climate Innovation Through British Research and Public-Private Partnership

Operation Blue Skies programme is co-funded by its industry partners and the Department for Transport (DfT) through the ATI Programme, a partnership between the Aerospace Technology Institute (ATI), the Department for Business, Innovation, Science and Trade (BIST) and Innovate UK. To ensure public funding directly advances sovereign scientific capabilities, 100% of the government grant funding is allocated directly to academic, non-profit, and aviation partners.

Google UK is participating on a pro-bono basis, contributing £1.4 million in-kind through AI research expertise, engineering time, and high-performance computing infrastructure to advance open climate science.

Contrails.org is working alongside the consortium partners to connect the scientific and operational pieces of the trial — assessing and integrating forecasts, shaping trial parameters and supporting data analysis so Operation Blue Skies can test whether contrail avoidance is safe, measurable and practical across oceanic airspace.

Consortium Roles and Scientific Verification

The multidisciplinary consortium brings together technical and scientific expertise across five key operational areas:

● Google UK: Developing AI models to predict and avoid warming contrails, while using machine learning and satellite imaging to track and verify impact.
● NATS (the UK’s leading air navigation service provider): Trial airspace operations, air traffic control coordination, conduct safety assessment and air traffic controller training.
● Contrails.org: Leading forecast assessment and integration, designing trial parameters, and supporting data analysis.
● Imperial College London & University of Cambridge: Evaluating trial outcomes and providing independent verification of climate impact.
● Met Office: Developing a new UK contrail forecast capability and ensuring meteorological accuracy throughout the trial.

Kemal Armada, Product Manager, Google said:

“Contrail avoidance has reached a pivotal moment. The question is no longer whether we can mitigate contrails, but whether we can make that mitigation work at the scale of the global aviation system.

This trial is an important step toward making that a reality, while demonstrating the strength of British research and innovation in developing practical solutions to one of aviation’s most important climate challenges.”

Ian Jopson, Director Sustainability at NATS, said:

“Decarbonising aviation will take a range of solutions, and understanding the role of contrails is an important part of that journey. This trial will allow us to test how contrail avoidance could work within the complex, highly coordinated environment of air traffic management.

By bringing together world-leading science and operational expertise, we can start to build the real-world evidence needed to understand whether this could make a meaningful contribution to reducing aviation’s overall climate impact.”

(1) Teoh et al 2024. Teoh, R., Engberg, Z., Schumann, U., Voigt, C., Shapiro, M., Rohs, S., and Stettler, M. E. J.: Global aviation contrail climate effects from 2019 to 2021, Atmos. Chem. Phys., 24, 6071–6093, https://doi.org/10.5194/acp-24-6071-2024, 2024.