It’s been 10 years since a Virgin Atlantic Boeing 747 flew from London to Amsterdam on the first test flight of an airliner powered by a mix of jet fuel and biofuels. Passenger flights in biofueled planes began three years later, and by June of this year, more than 130,000 flights had operated with what’s known more precisely as SAF, for “sustainable aviation fuel”. That isn’t to say that your next flight will be fueled by leftover oil from a deep fryer. Far from it.