Renewable jet fuels, also known as bio-jet fuel or Sustainable Aviation Fuel (SAF), are being developed as a drop-in alternative to traditional fossil-derived jet fuel. These fuels have similar energy density and meet all necessary specifications. Challenges include meeting strict standards, certification requirements, and economic hurdles. Various options like HEFA-SPK, FT-SPK, ATJ, and SPK/A are available for producing sustainable aviation fuels. These fuels are certified for limited use in commercial flights. The goal is to develop robust supply chains to meet the requirements of CORSIA, a scheme aiming to regulate and reduce CO2 emissions from international aviation. Feedstocks for SAF can be categorized into oil-containing biomass, lignocellulosic biomass, and sugars- and starch-containing biomass.