

Worldwide diesel/kerosene biofuel production is too low. Last time airbus made a demo on 100% biofuel made from algae, they bought the output of a whole year to run a single long haul flight.
There is a reason they say Sustainable Aviation Fuel (SAF) and not biofuel. They also need e-fuel / synthetic fuel made from hydrogen in addition to biofuel.
This make sense. It is so easy and natural to get “indebted” to someone from your social circle. You start recording all of that + some trade in that circle, and voilà money