It's just the same as the non-fossil versions of diesel like HVO100 and similar. Whether this fuel is "sustainable" or "emission free" of course depends on how

It's just the same as the non-fossil versions of diesel like HVO100 and similar. Whether this fuel is "sustainable" or "emission free" of course depends on how you see it. It will depend on what the source of the fats used is, and how those were produced, how much and what energy was used in the processing and so on. But at least it's significantly better than regular fossil fuel. An interesting thing about this is that there has been quite a lot of infrastructure built to create these fuels for road transport in the last decades. So if road transport is electrified but flight isn't, then all those resources could quite easily be redirected to make aircraft fuel instead. If I recall the interview correctly that I heard regarding the flight mentioned below, I think there are some countries that have enough biofuel production (currently for road transport) already, to replace all the aircraft fuel used domestically. The first commercial transatlantic flight with this type of fuel was just two days ago: https://apnews.com/article/transatlantic-flight-sustainable-aviation-fuel-e25e6a6c7f78e3cadb6c4dca29a37fc8 https://apnews.com/article/transatlantic-flight-sustainable-... > Is it snake oil? While renewable, the worlds entire production of snake oil would only make a small dent in the fuel needs of the airline industry.