Flight-level SAF accounting is becoming part of routine airline compliance and commercial reporting. Regulators and ICAO-calibrated schemes require operators to base claims of emissions reductions on documented purchase and blending records rather than informal statements. Practically that means airlines must connect fuel invoices and product transfer documents to specific uplift events and to the batches and proofs of sustainability provided by certified suppliers. Without that paper and electronic trail an operator cannot reliably reduce its offsetting or reporting obligation.

Why flight records matter to policy and to business

There are three audiences watching SAF flight records. First regulators need auditable inputs to verify compliance with schemes such as CORSIA and national SAF mandates. Second auditors and sustainability certification schemes require traceability up to the blending point in order to validate lifecycle calculations and prevent double claiming. Third commercial buyers and corporate customers require transparency so that a retired SAF certificate or a ‘‘book and claim’’ purchase has demonstrable integrity. Each audience demands a chain of custody that links production, blending, transport, uplift, and retirement of any SAF-related certificate. The concept is straightforward. The operational work is not.

Certification pathways that underpin safe deployment

From an aviation-safety perspective the industry relies on the ASTM and OEM-led certification system. New SAF production pathways enter operational use after evaluation under the ASTM D4054 practice and then annexation to ASTM D7566 as a permitted synthetic blend component. The D7566 annexes set blending limits and material property requirements that in turn allow finished blends to be reclassified under the conventional jet fuel specification. That process is the foundation that lets SAF be treated as a drop-in product for the existing fleet. Regulators, OEMs and operators rely on those standards when they approve operational use and when they decide whether higher blend ratios can be accepted.

In current practice several production routes are established and assigned annexes with explicit blend limits. Hydroprocessed esters and fatty acids HEFA, Fischer Tropsch FT-based routes, alcohol to jet ATJ, catalytic hydrothermolysis CHJ and a small number of other routes were accepted into ASTM D7566 by 2022 and typically carry blending ceilings (for example 50 percent for many annexes and 10 percent for some specific routes). Those annexes are the regulatory levers that determine whether an uplift in a fuel farm can be treated as SAF for safety and for emissions accounting.

Book and claim versus physical attribution: operational tradeoffs

There are three practical chain-of-custody models in use: physical segregation, mass balance, and book and claim. Physical segregation is conceptually simple but expensive and rarely scalable. Mass balance allows commingling while tracking volumes administratively through certified handlers up to the blending point. Book and claim decouples environmental attributes from physical molecules and issues a certificate or token that can be traded and retired by a claimant who may not have burned that particular litre of fuel. Each model has different implications for flight-level records. Mass-balance and physical segregation permit a direct link between uplift events and the sustainability paperwork that supports a CORSIA or national claim. Book and claim requires registries and retirement records to be auditable to avoid double counting. The industry white paper on SAF certificates and subsequent rulebooks published in 2022 set out precisely this architecture and the expectations for registries and certificate retirement.

Economic viability: price premia, bottlenecks, and the role of policy

At the operational level airlines face a simple math problem. SAF currently carries a material price premium compared with conventional jet kerosene. Public analyses and policy summaries from 2020 through 2022 consistently place that premium in the multiple-times band depending on pathway and feedstock. HEFA has generally been the lowest cost commercial option but is constrained by limited waste lipid feedstock. More advanced synthetic pathways are presently costlier and require larger capital expense to reach scale. That cost gap and restricted feedstock availability explain why SAF remained a small fraction of global jet fuel supply through 2022.

Because the premium is real airlines and fuel buyers are adopting two complementary strategies. One is to create long term offtake agreements and to co-invest in production to reduce risk and secure supply. The other is to use credible certificate markets and book-and-claim registries so that corporate demand can provide early demand signals even where physical logistics are not yet in place. Both strategies depend on robust record keeping: flight-level uplift data and proof of sustainability documents when fuel is physically uplifted, and registry records when certificates are traded and retired.

Practical implications for operators and auditors

1) Design your emission claim workflow around the blending point. The accepted line in international practice is that sustainability certification is traceable to the last certified entity up to the blending point. If you cannot trace a PoS or PoC back to that entity you should not count the quantity as SAF for compliance claims. Build your record retention and workflow accordingly.

2) Retain cross-references. Fuel invoices and product transfer documents must reference batch numbers that appear on proofs of sustainability. Flight level reporting that feeds CORSIA or national MRV systems should include those cross-references so a verifier can reconcile uplift mass to certified batch mass.

3) Treat registries as primary evidence for book-and-claim. If you acquire SAF certificates rely on registry retirement as the auditable event that supports your claim. Ensure the registry you use follows a published rulebook and can provide independent proof of issuance transfer and retirement.

4) Expect evolving blending limits. ASTM, OEMs and regulators are actively studying higher blend uses and 100 percent SAF pathways. Operators who intend to use higher blends will need to track fuel properties and operational performance data and make that data available to OEMs and regulators when seeking approvals.

Where policy makers can help

If the objective is to scale SAF affordably and reliably then policy must focus on three areas: predictable demand signals, standardized registries and interoperability, and targeted capital support for feedstock and production. Demand signals include mandated blending obligations or tradable instruments that are accepted in compliance MRV systems. Registry interoperability and standardization reduce verification costs and lower the risk of double issuance. Capital support shortens the time and lowers the upfront risk required to move novel pathways through ASTM D4054 testing and into production. Well designed policy does not short circuit certification. Rather it reduces financial friction while preserving the traceability rules that auditors and operators need.

Conclusion

Flight-level SAF records are not an administrative afterthought. They are the foundation for compliance with international schemes, for credible corporate claims, and for the market mechanisms that will allow SAF production to scale. Airlines and fuel suppliers should treat record architecture and registry interoperability with the same seriousness as fuel handling and safety compliance. For regulators the message is simple. If you want credible emissions reductions you must insist on auditable links between production, blending and retirement. If you want cheaper SAF at scale you must combine demand certainty with standards-based registries and properly targeted capital support so innovation can clear the certification gate and reach routine operational use.