There is a potentially greener e-fuel manufactured by the combination of green hydrogen with captured atmospheric carbon dioxide. This is a genuine low carbon solution but I wonder if a jet engine could be developed to run off the product, the second link hints at it. A pilot project run by Porsche and Siemens is running in Chile using renewable energy.
https://newsroom.porsche.com/en/2020...els-23021.html
https://arstechnica.com/cars/2022/04...-fuel-startup/