Sustainable aviation fuel is known as SAF. It is made from renewable feedstock and has a chemistry that is remarkably similar to that of conventional fossil jet fuel. Compared to the conventional jet fuel it replaces, using SAF reduces carbon emissions during the fuel's lifetime. Cooking oil and other non-palm waste oils from animals or plants are some examples of typical feedstock, as are solid waste from homes and businesses such as packaging, paper, textiles, and food scraps that would otherwise be disposed of in landfills or burned. Other potential sources include energy crops like fast-growing plants and algae, as well as forestry waste like waste wood.

In comparison to traditional jet fuel, SAF can significantly lower life cycle GHG emissions depending on the feedstock and methods utilized to create it or even have a net-negative GHG impact, according to some proposed SAF routes. According to the U.S. Environmental Protection Agency, aviation GHG emissions account for 9%–12% of all transportation-related GHG emissions in the country. SAFs' reduced carbon intensity makes them a significant GHG emission reduction strategy.

Jet fuel has a high energy density compared to its weight, which has made the commercial flight possible. We are dependent on this type of fuel in aviation since there are now no other practical alternatives for swiftly moving large crowds of people over extremely great distances. Per economy ticket, a roundtrip journey from London to San Francisco emits around 1 tonne of CO2e. It is imperative to take action to minimize aviation's carbon emissions because that sector of the economy is predicted to increase to carry over 8 billion people by 2050.

In the US, it is possible to collect 1 billion dry tonnes of biomass annually in a sustainable manner, which would yield 50–60 billion gallons of low-carbon biofuels. These sources consist of:

This enormous resource has adequate feedstock to manufacture high-value bioproducts and renewable chemicals in addition to greater quantities of drop-in low-carbon fuels to fulfill the expected fuel needs of the U.S. aviation industry.

Based on the sustainable feedstock utilized, the production process, and the supply chain to the airport, SAF offers a remarkable decrease in carbon emissions of up to 80% over the fuel's life cycle compared to the conventional jet fuel it substitutes.

SAF can be blended with conventional jet fuel up to 50%, and all quality checks are carried out as they would for conventional jet fuel. The mixture is then given a new Jet A or Jet A-1 certification. No modifications to the fuelling infrastructure or for an aircraft wishing to use SAF are necessary because it may be handled in the same manner as conventional jet fuel.

Currently, SAF is more expensive than conventional fossil jet fuel. The existing accessibility of sustainable fuel sources and the ongoing advancement of innovative manufacturing technology is responsible for this. As the technology matures it will become more cost-effective and so the assumption is that it will become less expensive for customers.

Compared to the conventional jet fuel it replaces, it might result in a lifespan carbon reduction of up to 80%. The SAF will be crucial in helping the aviation sector reach its carbon reduction goals, but there are still many other ways we can cut carbon emissions. Wide-ranging options exist for the sector to reduce its carbon footprint, including smarter operations, more energy-efficient aircraft design, and the creation of upcoming technologies like electrification. Over the long run, that will require funding in sophisticated technology to generate feedstock more proficiently at a larger scale and investment in the development of sustainable and scalable feedstock options.