Operation Blue Skies takes off: landmark trial to test AI-driven contrail avoidance

Operation Blue Skies takes off: landmark trial to test AI-driven contrail avoidance Sarah Collins Tue, 08/18/2026 - 15:29

Backed by the UK Government, 'Operation Blue Skies' brings together partners, including the University of Cambridge, to evaluate AI-driven flight path adjustments across North Atlantic airspace.

Operation Blue Skies is a £5 million, 30-month programme, partly funded by £2.65 million from the Department for Transport. It includes two operational trials to be 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.

Contrails form when water vapour in jet-engine exhaust condenses and freezes around soot particles and other aerosols in the cold, humid air of the upper atmosphere. Persistent warming contrails trap outgoing heat, accounting for roughly one-third of aviation's total climate impact.

Atmospheric modelling shows that the Shanwick airspace accounts for approximately 5% of global contrail warming. A significant part of this warming is concentrated in the winter season between November and February. Operation Blue Skies will 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.

In addition to the University of Cambridge, the Operation Blue Skies consortium includes Google, the Department for Transport, the Met Office, NATS, Contrails.org, and Imperial College London.

The Cambridge and Imperial researchers will be evaluating trial outcomes and providing independent verification of climate impact.

“Contrail avoidance could drastically reduce the global climate impact of aviation, at minimal cost to passengers and companies,” said Professor Steven Barrett, Regius Professor of Engineering at the University of Cambridge. “Operation Blue Skies is a big step forward in this process, as it will test the ability of the UK to reduce contrail coverage at an airspace-wide scale and in a real-world setting. It’s an exciting step in building a more sustainable aviation industry.”

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

“This is a world-first, and it's British ingenuity leading the way,” said Keir Mather, Minister for Aviation, Maritime and Freight. “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.”

The 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 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.

“Contrail avoidance has reached a pivotal moment,” said Kemal Armada, Product Manager at Google. “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.”

Steven Barrett is a Fellow of Gonville & Caius College, Cambridge.

oversnap via Getty Images

Jet passing in front of the moon

Yes