The vital question for the future of aviation is: how do we tackle greenhouse gas (GHG) emissions from air transport and their serious impact on the climate? There are not many technological options available. Electric-driven aviation is, for the next decades, only suitable for short distance flights. The use of bio-based kerosene is confronted by NGOs as putting unacceptable pressure on natural resources, such as land and biodiversity. It is also hampered by quality and standards issues for different biomass sources and conversion processes.