Broader contextAviation in the context of the environment is often seen in the public eye as being responsible for considerable environmental detriment. This, coupled with a limited supply of conventional jet fuel, has resulted in the sector searching for alternative fuels. Recent activity has demonstrated incident free operation—without airframe or engine modification—of fuel refined from both gas and biomass feedstocks. Unfortunately, diversification away from crude oil does not necessarily improve both environmental credentials and supply security. Considering the sector's environmental footprint, the best case test flight achieved a 30% reduction in emissions. The reduction, however, only equates to a potential saving of 0.78% of global CO2emissions. Realising this saving across the sector would require 6% of the world's arable land or 3.2% of global surface area if feedstock (Jatropha) was grown on marginal land. Refinement of gas or coal (Fischer Tropsch process) provides for sufficient feedstock volumes to diversify supply, however, the process is at best comparable to a modern crude oil refinery in terms of well to wake emissions. It is anticipated that market forces will allocate feedstock to sectors which provide the highest level of abatement at the lowest cost, meaning that aviation will need to compete to secure fuel.