Air France has adjusted the flight paths of 130 transatlantic routes to avoid contrails, which are artificial clouds formed by aircraft engines. These contrails can contribute to global warming by trapping heat in the atmosphere. From February to April 2026, Air France tested new flight paths to avoid areas where contrails are most likely to form and remain visible for long periods. During this two-and-a-half-month trial, the airline operated approximately 12,000 long-haul flights, rerouting 130 of them between France and North America, Mexico, or the Caribbean. The changes were made in collaboration with two French firms, Estuaire and Klima, which focus on reducing aviation’s environmental impact. According to Air France, these adjustments helped avoid the emission of around 22,000 tonnes of CO2, without causing any delays to passengers. Contrails form when water vapor from aircraft exhaust condenses and freezes in cold, humid air, often around soot particles emitted by the engines. These clouds can trap heat, contributing to global warming. While contrails from commercial flights make up only 3% of all contrails, they are responsible for 80% of the warming effect caused by such clouds. To minimize this impact, airlines must avoid flying at altitudes and in regions with high humidity and low temperatures, where contrails are most likely to form and persist. These conditions typically involve humidity levels of up to 130% or even 140%, combined with temperatures cold enough to cause freezing. The test conducted by Air France was part of a larger European Union initiative called Ciconia, which includes collaboration from major aviation companies like Airbus and Boeing, as well as airlines such as EasyJet and Swiss, along with research and regulatory bodies. The project aims to develop strategies to reduce the climate impact of aviation through technological and operational improvements. Meanwhile, a conference on the topic of contrails is being held in Paris on Monday, organized by French Green deputy Christine Arrighi and the environmental think tank Transport & Environment. The discussions will focus on the challenges and opportunities for reducing aviation’s contribution to global warming. Air France plans to apply the lessons learned from this test to more complex regions with higher air traffic. While the North Atlantic route was relatively straightforward for rerouting flights, other areas will require more sophisticated planning and coordination. The airline is aiming to expand its efforts to reduce contrails, which it views as an important step toward achieving its climate goals. As the aviation industry continues to explore ways to cut emissions, avoiding contrails is emerging as a practical and effective measure that can be implemented without compromising flight schedules or passenger comfort.