Air France has trialled small route and altitude changes on transatlantic long-haul flights to reduce the climate impact of persistent contrails, with February-to-April testing on about 4,300 flights showing no passenger delays during the trial. The airline identified 245 high-risk flights, rerouted 130 of them and estimated that the changes avoided about 22,000 tonnes of CO2-equivalent impact across operations between France and North America, Mexico and the Caribbean.
The experiment focused on weather conditions known to favour persistent contrail formation, using targeted adjustments rather than broad network changes. On rerouted flights, the contrail impact fell 57%, while the reduction across the full test set was 8%. Air France worked with French startups Estuaire and Klima on the project, which formed part of the EU-backed CICONIA programme.
The results point to a mitigation approach that could be scaled more widely, although any broader rollout would depend on air traffic control approval and closer operational coordination. Air France also said a small share of the flights accounted for a disproportionate share of the climate effect, with 3% of the studied services responsible for 25% of total contrail impact.