Ambitious decarbonization strategies for the aviation sector rely heavily on low-carbon alternative fuels. Unlike passenger vehicles, electrification of aircraft is technologically difficult, and this sector may be reliant on liquids fuels through the end of this century. Delivery of low carbon advanced fuels has been slow even to the road sector. Is it realistic to expect decarbonization of fuel used in aviation, and if so, what needs to happen to achieve it,This series aims to understand the challenges and policy solutions to delivering low carbon fuels to aviation.