United Airlines promises sustainable flying - but experts aren't convinced

United has sought to position itself at the front of the industry's efforts with a pledge to become '100% green' despite enormous obstaclesOn 1 December, a United Airlines passenger plane flew from Chicago to Washington powered solely by fuel made from cooking oils, agricultural waste and other materials rather than fossil fuels.Billed by the airline as the world's first fully-loaded passenger flight to run on 100% sustainable aviation fuel (SAF), it was United's latest attempt to demonstrate its climate credentials. United's CEO Scott Kirby called it "a significant milestone" for efforts to decarbonize the industry. Continue reading...