Hydrogen fueled jets?

https://www.stuff.co.nz/travel/gree...t-engine-could-revolutionise-green-jet-travel

"As with cars, the sheer weight of batteries poses a challenge for aviation. And for a machine aiming to defeat gravity, this is a problem neatly summed up by Newby. "If I take kerosene as my reference point, weight for weight, hydrogen is three times better, batteries are 60 times worse," he says. "That's the challenge for batteries."

As for hydrogen, storing the gas, keeping components cool and gathering enough of the stuff are all challenges that can be overcome in the long term.
The gas is seen as an attractive alternative because when burnt efficiently it produces only water as a by-product. Used in high-temperature environments like a jet engine, it can produce nitrogen dioxide, another gas policymakers want cut because it is linked to damage in lung health.
Companies such as ZeroAvia in Britain are developing hydrogen-driven smaller aircraft using fuel cells to generate electricity. But for Rolls-Royce, hybrids and greener fuels will be the stepping stone."