A recent study reveals that the climate-warming effect of jet contrails could be significantly reduced by adjusting flight paths, costing less than £4 per flight. Contrails, formed by plane exhaust in cold humid air, are estimated to double the warming impact of aviation’s fossil fuel use. As discussions begin at the UN climate conference, COP29 in Baku, experts emphasize that minor changes to a small percentage of flights could cut contrail warming by over 50% by 2040. The study highlights this solution as a cost-effective alternative amidst the ongoing search for sustainable aviation fuels.