meanwhile:
British boffins say aircraft could fly on trash, cutting pollution debt by 80%
Sustainable aviation fuels (SAFs) made from sources other than fossil fuels have the potential to reduce emissions by up to 80 percent
SAFs are primarily made from corn and other crops, but waste resources have also been converted into synthetic jet fuel
The US Department of Energy (DoE) lists wood mill waste, agricultural residues, fats and greases, municipal solid waste, and other less-than-appealing sources as possible base materials for SAF
https://www.energy.gov/eere/bioenergy/sustainable-aviation-fuels
A report from the Royal Society released earlier this year concluded that the UK would need to devote half of its existing farmland to SAF production, or more than double its renewable electricity supply, to meet net zero aviation goals.
Rolls-Royce and Easyjet tested the world's first hydrogen aviation engine late last year,
https://www.theregister.com/2022/11/29/rollsroyce_easyjet_hydogen_engine/
but the test was stationary and no timetable for getting the engine flying has been established. Airbus has since joined the project, with plans to get a hydrogen-powered jet in service by 2035 it's hoped.
@ecksmc A weird thought -- could this change the global water cycle for the better?
Just thinking about the energy required to move a modern airliner across long distances, and how many there are at any given time, could we be looking at a way to get even a little water cycling back through desert regions?
That'd be interesting. I need to look into this more.