Synthetic Aviation Fuel: What It Is and Where Sustainable SAF Fits

Sustainable aviation fuel (SAF) has become the aviation industry's clearest path to lower-carbon flight, but the term covers a range of very different fuels and production methods. In this guide, we break down what SAF actually is, the main pathways used to make it, and where synthetic SAF produced from captured carbon dioxide (CO₂), like AIRMADE® SAF, fits in.

Sustainable aviation fuel (SAF) is best understood as an innovative fuel produced from a variety of feedstocks, independent from reliance on those that are finite, while promising a cleaner future for the planet. It’s an industry-wide category that spans several production pathways and feedstocks, including waste oils and agricultural residues, as well as captured carbon dioxide. Regardless of origin, all SAFs must meet aviation's strict fuel-quality standards and must be compatible with the aircraft flying today.

At AIRCO, our SAF, also called synthetic aviation fuel, is made from captured CO₂ and low-carbon hydrogen (H2) rather than from biological feedstocks. AIRMADE® SAF is manufactured through a closed-loop system. It can be carbon-neutral if produced from biogenic or atmospheric CO₂. Once the SAF is combusted in the aircraft, the emitted CO₂ returns to the atmosphere. The electricity powering this process is derived from a variety of energy sources, including nuclear, geothermal, or hydro.

Aviation is uniquely difficult to decarbonize: batteries and hydrogen aren't yet viable for long-haul flight, and aircraft stay in service for decades. That leaves the fuel as the fastest available lever. According to a scientific study titled , “Pathways to net-zero emissions from aviation,” improvements in aircraft energy efficiency could collectively mitigate up to 27% of CO₂ (equivalent to 1.2 billion tons) of projected business-as-usual aviation emissions by 2050. This is meaningful, but nowhere near enough on its own. The rest has to come from the fuel.

Corporations are increasingly more focused on addressing their GHG emissions. SAF is projected to play a critical role not only in helping the aviation industry reduce its emissions but in allowing corporations with extensive corporate travel to reduce their Scope 3 emissions.

Another major benefit of SAF is that it reduces dependence on a single, finite resource. SAF pathways rely on novel sustainable feedstocks, which offer an opportunity to diversify the sources of the fuels that the modern economy depends on. By diversifying feedstocks and reducing reliance on fossil fuels, SAF offers additional benefits, including energy security and supply chain diversification.

The industry has set the destination. The International Civil Aviation Organization (ICAO) has adopted a Long-Term Global Aspirational Goal (LTAG) for international aviation of net-zero carbon emissions by 2050 in support of the UNFCCC Paris Agreement's 1.5 °C goal. Today, the gap is still wide. SAF accounted for roughly 0.6% of global jet fuel use in 2025, which is exactly why the choice of production pathway and how fast each can scale matters so much.

Not all SAF is made the same way. There are several regulatorily-approved pathways, each defined by its feedstock, conversion process, and the extent to which it can be blended with conventional jet fuel. The table below compares the main routes currently in use or under development today.

Most SAF produced today depends on biological feedstocks, which ties its growth to the supply of waste oils and crops. Synthetic SAF breaks that link. Unlike other SAF pathways that rely on biological feedstocks, AIRMADE® SAF is a groundbreaking synthetic fuel that requires only hydrogen and carbon dioxide (biogenic or non-biogenic) as a feedstock.

Our AIRMADE™ Technology allows us to turn CO₂ into a renewable feedstock. By using CO₂ from a variety of sources, we ensure that AIRMADE® SAF operates within the natural carbon cycle and does not add additional emissions to the atmosphere.

Beyond what sets it apart from other SAF, synthetic SAF also shares the advantages every SAF has over conventional jet fuel, starting at the point of combustion. The cleaner-burning properties help reduce harmful non-CO₂ emissions, enhancing local air quality and contributing to a healthier planet.

SAF typicallyalso contains fewer aromatic components compared to conventional jet fuels. This means there is less particulate matter being emitted from the engines, which in turn reduces the formation of contrails (condensation trails), or the white lines you see in the sky behind high-flying jets. They're known to contribute to climate change by trapping outgoing longwave radiation. According to several studies, contrails are responsible for around 35% of all planetary warming from aviation. NASA and the German Aerospace Center (DLR) conclude that sustainable, cleaner-burning jet fuels can reduce ice crystal contrail formation at cruising altitude by 50%-70%, lessening a flight's environmental impact.

Our AIRMADE™ Technology is a scalable technology solution that transforms carbon dioxide into an endless resource. Here is the step-by-step process.

1. CO₂ Capture: We work with partners to acquire our CO₂. They capture it from places such as industrial plants before it's emitted into the atmosphere. The CO₂ is then cooled, pressurized, and liquefied, and sent to our facility in tanks, ready for the next stage.
2. Electrolysis: On-site electrolysis splits water into hydrogen and oxygen. The oxygen is vented as clean air, while the hydrogen is sent to the carbon conversion reactor.
3. Carbon Conversion: This is the core of the AIRMADE™ Technology. Here, the captured CO₂ and H2 meet in a tubular, fixed-bed flow system filled with a proprietary catalyst. The catalyst pellets facilitate a chemical reaction that produces a reactor liquid composed of an oil (or hydrocarbon) layer and an aqueous (or water) layer.
4. Separation: The oil is separated from the water, resulting in synthetic crude.
5. Post-Processing: The post-processing stage is an integral step that aligns the final product with the rigorous requirements of engine and aircraft Original Equipment Manufacturers (OEMs) and the property requirements of the American Society for Testing and Materials (ASTM) D7566 specification.
6. Upgrading: The synthetic crude is processed in reactors to produce a fully formulated synthetic fuel. This includes the following steps:
   1. Hydrogenation: Conversion of the raw fuel mixture into saturated hydrocarbons (paraffins) by removing impurities, essential for creating a 100% drop-in SAF such as AIRMADE® SAF.
   2. Oligomerization/Alkylation: Transformation of the paraffins and aromatics into higher molecular weight compounds within the jet fuel range
   3. Hydrogenation Pt. II: Conversion of aromatics to cycloparaffins through saturation of carbon-carbon double bonds, improving SAF's density and freezing point.
   4. Distillation: A specialized distillation process separates the synthetic middle distillate by boiling point into jet fuel, diesel, and other fuel components.

Some of the primary hurdles to a global SAF rollout include funding for research and development, limited networks that impede logistics and operations, and feedstock sources (such as waste oils and agricultural residues), which can constrain the industry's expansion.

These challenges are as much economic and structural as they are technical. For synthetic aviation fuels (SAFs) to become widely available, several challenges persist, including high production costs, policy uncertainty, green premium, and the "who pays" question, feedstock aggregation and distribution at scale, and the complexities of securing capital for novel projects.

A modular, CO₂-based pathway such as AIRCO’s MAD Fuel System™ is built to address several of these at once. It isn't tied to limited biological feedstocks and can be deployed where CO₂ and power are available.

When we better understand what synthetic aviation fuel is and its impact on the aviation industry and environment, we can more effectively implement this technology, influence policy, and carve out a path toward long-term change. SAFs, with their potential to dramatically reduce lifecycle carbon emissions, are not just an option; they are a critical variable in the aviation industry's carbon equation.

Connect with our team to learn more about AIRMADE® SAF and the MAD Fuel System.

Is sustainable aviation fuel more expensive than conventional jet fuel?

Yes, at least for now. The current technologies for SAF production are more expensive than conventional jet fuel production, making SAF less economically competitive without subsidies or incentives. The gap is significant enough that industry groups estimated SAF added roughly USD 3.6 billion to airline fuel costs in 2025, and closing that "green premium" is one of the main barriers to faster adoption.

How much sustainable aviation fuel is used today?

Very little, relative to demand. Global SAF production reached about 1.9 million tonnes (roughly 2.4 billion liters) in 2025, about 0.6% of total jet fuel use, and is projected to reach around 0.8% in 2026. Volumes have roughly doubled year over year, but they remain a small fraction of what the industry needs to hit its 2050 targets.

Who uses sustainable aviation fuel?

Commercial airlines are the primary users, blending SAF into their normal fuel supply at airports per ASTM regulations. AIRCO's AIRMADE® SAF partners include airlines and fuel suppliers such as Virgin Atlantic, JetBlue, Air Canada, Air France–KLM, Alaska Airlines, and Avfuel, and the fuel has been demonstrated with the U.S. Department of Defense, including the first unmanned flight powered by 100% CO₂-derived synthetic jet fuel.

Does sustainable aviation fuel require changes to aircraft or airport infrastructure?

Not always. AIRMADE® SAF is a drop-in fuel, meaning it is chemically compatible with existing aircraft engines, storage, and fueling infrastructure and requires no modifications to use. However, there are currently research efforts to develop variations of SAF that may provide operational or environmental benefits but that will require new infrastructure and aircraft.

What policies and incentives support sustainable aviation fuel adoption?

SAF policy differs sharply by region. In the United States, support has come primarily through federal incentives, and the specifics have shifted recently. The Inflation Reduction Act created a dedicated SAF tax credit (Section 40B) worth $1.25 to $1.75 per gallon based on a fuel's lifecycle greenhouse gas reduction. That credit expired at the end of 2024 and was succeeded by the broader Clean Fuel Production Credit (Section 45Z). In 2025, the One Big Beautiful Bill Act reshaped Section 45Z, removing the SAF-specific rate (which lowered the maximum to $1 per gallon), requiring qualifying fuels to be made from feedstock grown in the United States, Mexico, or Canada, and extending the credit through the end of 2029. Beyond the credits, the IRA funds the FAA's Fueling Aviation's Sustainable Transition (FAST) grant program for companies that produce, transport, blend, or store SAF, while other laws support airport fueling infrastructure and a Department of Defense SAF pilot program. These efforts fall under the federal SAF Grand Challenge, which aims to achieve at least 3 billion gallons of U.S. SAF production per year by 2030. The landscape remains in flux. Bills before the current Congress would variously reinstate the SAF-specific credit rate and extend it into the early 2030s, or repeal the fuel credits altogether.

Other major markets lean on mandates instead. The EU's ReFuelEU Aviation regulation requires a minimum SAF blend rising from 2% in 2025 to 70% by 2050, with a dedicated sub-mandate for synthetic e-fuels beginning in 2030, and the UK's JetZero strategy takes a comparable mandate-based approach.

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References:

1. https://www.energy.gov/cmei/fuels/sustainable-aviation-fuels
2. https://www.nature.com/articles/s41893-022-01046-9
3. https://trellis.net/article/corporations-buy-sustainable-fuel-certificates-address-air-travel-emissions/
4. https://www.icao.int/SAF
5. https://www.iata.org/en/pressroom/2025-releases/2025-12-09-04/
6. https://www.nytimes.com/2023/08/08/climate/curbing-contrails-a-climate-solution-in-the-skies.html
7. https://www.nasa.gov/news-release/nasa-dlr-study-finds-sustainable-aviation-fuel-can-reduce-contrails/
8. https://www.defenseandmunitions.com/news/airco-dod-completes-first-of-its-kind-demonstrations-using-co2-derived-drop-in-fuel/
9. https://www.congress.gov/crs-product/IF12757
10. https://transport.ec.europa.eu/transport-modes/air/environment/refueleu-aviation_en
11. https://www.gov.uk/government/publications/jet-zero-strategy-delivering-net-zero-aviation-by-2050