Some countries are imposing extra fees on conventional aviation fuel. This is new - Air ticket prices to go up as Singapore mandates sustainable fuel for departing flights from 2026 [1].
Many countries have wanted to tax aviation fuel for a long time, but the economic downsides of having fewer planes visit your nation far outweighs any taxes collected.
I don't see how requiring SAF would be any different.
I don't see how requiring SAF would be any different.