A plane fueled by fat and sugar has crossed the Atlantic Ocean

Biofuels like this have some very significant scale constraints, and quite literally amount to burning food. Per the article:

Virgin Atlantic’s 100% SAF flight is a one-time stunt, and the airline won’t regularly offer all-SAF flights. Standard jet engines aren’t designed to run on only sustainable fuel, and it is too expensive and rare for it to be practical for airlines to run all-SAF routes.