Transatlantic flying is fuel intensive. That simple fact frames the SAF debate for operators and crews. On a long haul hop across the Atlantic every extra cent per litre is multiplied by tonnes of fuel burned, and that shows up straight away in airline operating costs, fuel planning and route economics. Policymakers and operators are rightly asking whether the current price premium for sustainable aviation fuel is justified by the safety, operational and climate benefits it delivers.
From an operational vantage point SAF is mostly a drop in replacement. Multiple approved SAF pathways are certified into the ASTM D7566 family and in 2023 an alcohol to jet pathway gained approval that allows up to a 50 percent blend for approved synthetic and bio-based blendstocks. That means modern airframes and engines can accept SAF blends without airframe or propulsion redesigns, and fuel-handling at airports remains familiar to ground crews.
Safety and operational effects are not just about combustion chemistry. Lower aromatic content in many SAFs reduces soot and non-volatile particulate emissions. Flight researchers saw substantial reductions in contrail ice nuclei and contrail optical depth with low aromatic blends in flight experiments, which translates into lower climate forcing from contrails and also fewer soot particles passing through engines. Reduced soot load can mean cleaner combustor chambers and turbine stages, with potential downstream benefits for engine maintenance intervals and on-wing performance. Those are tangible operational payoffs that matter to pilots and maintenance crews.
So where does the economics come in? In 2022 nearly all SAF then produced was purchased by airlines even though it carried a clear price premium. Airlines reported paying several hundred million dollars above fossil jet fuel cost for that supply, illustrating strong demand but limited production. Production volumes in the early 2020s were tiny relative to global jet-fuel use, which is why market prices stayed elevated.
Independent analyses from energy agencies and the literature around 2023 indicated that first generation HEFA and other bio-based SAFs were commonly priced at roughly two to three times fossil jet fuel on a production cost basis, with power to liquids and electrofuel routes modelled at even higher multiples today. Those cost gaps are sensitive to feedstock availability and renewable electricity prices, but they are real and they drive the economics airlines face when deciding how much SAF to buy and where to deploy it.
The EU has moved to reduce market uncertainty by creating a demand mandate. ReFuelEU sets a minimum SAF share at EU airports starting with 2 percent in 2025 and rising thereafter, and it contains provisions to stop so called tankering by requiring operators to refuel with the fuel necessary for the flight when departing EU airports. That is operationally important because tankering to avoid refuelling at an SAF-mandated airport would defeat the policy and could create unusual fuel-planning behavior. Mandates create demand certainty, but they also compress the transition window for SAF production and can magnify short term price effects if supply is not yet scaled.
For transatlantic sectors the best near term economic case for SAF is targeted deployment where benefits per litre are largest. Long haul flights consume more fuel per departure so every litre of SAF used offsets more lifecycle CO2 and more contrail formation potential than on a short sector. In practical terms that means using limited SAF supply on trunk routes and on aircraft types where the emission reduction per flight is maximized. That is a simple allocation principle but it has to be balanced against airport supply logistics, contractual price premiums, and network scheduling constraints.
On the safety side there is no evidence that certified SAF blends compromise airworthiness when used within approved limits. European and aviation safety regulators have stressed that sustainability must not come at the expense of safety, and safety authorities have been given explicit roles to ensure fuel specifications and sustainability criteria are reconciled with technical and operational standards. That regulatory attention is a necessary check as SAF volumes grow and new feedstocks and synthetic routes enter the market.
So what should operators and regulators do now? My practical take from the flight deck is threefold:
1) Prioritize targeted SAF use where it delivers the most environmental and operational benefit per litre. That means trunk and transatlantic routes as a near-term priority while supply is constrained.
2) Push for demand signals tied to stable policy frameworks rather than abrupt mandates that outpace supply. Predictable, phased mandates and purchase incentives reduce the risk of market distortions and excessive short-term price spikes. The ReFuelEU mandate is a start, but it needs accompanying measures to scale feedstock and production.
3) Keep safety and technical oversight front and center. Certify new pathways, monitor fuel-handling, update maintenance baselines where warranted, and keep pilots and maintainers informed. The earliest SAF deployments are operational test beds; capture the data and feed it back into regulatory and airline maintenance planning.
Bottom line: SAF brings measurable safety adjacent benefits in the form of lower soot emissions, reduced contrail climate forcing and drop in potential engine contamination. Those benefits are real and operationally valuable on transatlantic services. The economic reality in late 2023 is that SAF is still a premium product. Without stronger policy support and rapid scale up in production, that premium will continue to shape who uses SAF and where. From a pilot and operator perspective the smart play is to match scarce SAF to flights where you get the largest safety and climate return per litre, while pressing for stable policies and investment that will drive cost parity over the decade ahead.