The emerging geopolitics of sustainable aviation fuel: Policy architectures, book-and-claim and european strategic dependencies

Sustainable Aviation Fuel (SAF) is becoming a strategic component of aviation decarbonization, but its expansion depends on technological, economic, institutional, and resource conditions. This study compares the combinations of policy instruments, structural production characteristics, and market-governance arrangements observed in the European Union, the United States, the United Kingdom, Japan, Singapore, and Brazil, and considers the potential strategic vulnerabilities these configurations suggest, particularly for the European Union. The comparative qualitative policy analysis draws on peer-reviewed literature, legislation, regulatory documents, and institutional sources, organized through a single four-part framework: policy-instrument mix; structural production conditions; market and governance conditions; and potential strategic vulnerabilities. The cases display different configurations. The European Union and the United Kingdom emphasize mandatory demand; the United States relies more heavily on producer incentives; Japan and Singapore emphasize coordination and supply security; and Brazil combines established biofuel capabilities with a developing SAF framework. These observations do not identify causal effects or rank the configurations. Instead, they indicate possible exposure to feedstock, production, finance, policy-continuity, import, and certification constraints. Book-and-Claim is examined as a governance arrangement that separates environmental attributes from physical fuel flows; its practical contribution depends on credible certification, verification, registry governance, and interoperability. For the European Union, the comparison suggests that regulatory leadership may coexist with external supply and institutional dependencies. The concept of resilient interdependence is therefore proposed as a policy lens rather than a measured outcome.