This chapter delves into the imperative need for green and sustainable aviation fuels, highlighting the urgency for the aviation industry to reduce its carbon footprint. It thoroughly examines various bio-jet fuel conversion technologies, including Fischer–Tropsch synthetic paraffinic kerosene (FT-SPK), hydroprocessed esters and fatty acids (HEFA), synthesized iso-paraffins (SIP), FT-SPK with aromatics (FT-SPK/A), alcohol-to-jet (ATJ), hydroprocessed hydrocarbons SPK (HH-SPK), and catalytic hydrothermolysis jet (CHJ), which were certified in the American Society for Testing and Materials (ASTM) standard in sequence. These technologies have been evaluated for their technological routes, economic feasibility, environmental impact, and scalability, providing a comparative analysis of their strengths and limitations and discussing their potential to transform the aviation sector into a more environmentally sustainable one. The HEFA and FT-SPK routes have been identified to be the most economically viable, while ATJ is not financially viable under the current prevailing market price for crude oil. The necessity of the presence of aromatics within SPK is highlighted, with the aim of achieving satisfactory compatibility with the current infrastructure. The commercial practices and flight tests of aviation biofuels are also discussed. Overall, this chapter significantly contributes to understanding the potential of aviation biofuels in achieving environmental sustainability in the aviation sector.