For very large aircraft and very long distances, low-carbon alternative fuels are at present the only viable replacement in near term for fossil fuels, contributing towards sustainability targets before electric and hydrogen technologies will become mature. Since the interest on Sustainable Aviation Fuels (SAF) is growing, more pathways will be introduced and approved in the near future. The scientific research is mainly focusing on the production of advanced biofuels and ekerosene. Biofuels from biomass or waste (cooking oils, fats) and advanced biofuels that are synthesized from solid feedstock, biomass like crops, or algae. E-fuels or e-kerosene are synthetic fuels or synfuels, synthesized from hydrogen and carbon dioxide taken from industrial, biomass or direct-air capture. For the advanced biofuels, beyond existing modern technologies for SAFs production, novel pathways are proposed, mainly related to the conversion and fermentation of feedstocks to alcohol and then biofuels. The main techniques are: Alcohol to Jet Synthetic Kerosene with Aromatics (ATJ-SKA), approved by ASTM (American Society for Testing and Materials) in 2023, and the novel technologies L-ETH-Jet, Biochemical conversion of lignocellulose to ethanol process; SYN-FER-J, Gasification, syngas fermentation to ethanol process; S-ETH-J, Sugarcane juice to ethanol by sucrose fermentation process. E-fuels are produced using renewable energy for fuel synthesis. New technologies for e-fuels production, like power-to-liquid process are promising for reducing greenhouse gas emissions in aviation. They are not yet available on the market, but there is a growing interest from various companies in establishing production facilities. Moreover, a growing enthusiasm for the electrochemical route has potential to improve e-kerosene production.