Biofuels/ethanol/SAF are much the same; often derived from corn.
In many cases, the oil/gas/electricity used for harvesting, processing, cracking etc. is actually comparable to or exceeds the carbon released by simply drilling for and burning the oil in the first place.
The issue with aviation hydrogen is… well, lots.
Fuel cells are heavy and direct combustion is inefficient and tougher than burning kerosene.
Aircraft typically use the wing structural members as the fuel tank walls. Both cryogenic and pressurised options make that a non-starter.
Lower density means much bigger tanks.
Self-vapourising fuel is a major crash issue.
Round trip efficiency for H2 is still terrible.
Plants may not be particularly efficient per km^2 but arable land isn’t actually that hugely scarce.
Reducing aviation is really the only thing that’s actually going to work.