Executive summary This paper explores the techno-economic feasibility of replacing fossil-fuelled airport buses with alternative low-emission technologies such as retrofitted diesel-to-electric, battery-electric and hydrogen buses. The aim is to provide actionable insights for airports seeking to decarbonize ground operations and improve local air quality. Using a robust total cost of ownership (TCO) model – validated through industry research and stakeholder interviews – the analysis explores how capital, operating, maintenance and infrastructure costs affect airport bus operations and their costs. Key findings include: –Technology assessment: Retrofitted diesel vehicles with electric powertrains present a cost-effective transitional solution that enables rapid emissions reduction without the need to procure an entire fleet of battery-electric buses. Battery-electric buses offer zero tailpipe emissions and are increasingly cost- competitive over their life cycle, especially where airport routes are predictable and charging infrastructure can be efficiently deployed and operated alongside flight schedules. Hydrogen buses (using fuel cell batteries or internal combustion engines (ICE)) provide greater range and faster refuelling, making them suitable for larger airports with intensive duty cycles, though they currently face higher upfront and infrastructure costs. –TCO: The analysis, based on a reference European hub airport, reveals that retrofitted electric buses can offer the lowest TCO per kilometre (km), making them attractive for operators with budget constraints compared to newer diesel fleets. New battery-electric buses require higher upfront investment but can deliver lower operating costs over time, particularly when supported by government incentives. Hydrogen buses, while operationally flexible, are probably the most expensive option at present due to technology and infrastructure costs. –Operational and strategic considerations: The choice of technology depends on each airport’s operational profile, financial capacity and long-term sustainability goals. Sensitivity analysis highlights that driver salaries, utilization rates and the availability of subsidies are the parameters that affect TCO the most. While further research is recommended to assess more detailed airport load profiling, battery degradation modelling and real-world retrofit performance data, pragmatic recommendations for airports include: –Adopting common electric vehicle (EV) charging and hydrogen refuelling standards to streamline infrastructure deployment and interoperability, including between ground equipment and future aircraft. –Integrating renewable energy sources to power electric fleets and reduce life-cycle emissions, and renewable transport fuels where reliance on non-electric powertrains is envisaged. –Exploring second-life battery applications to maximize asset value, circularity and sustainability. –Leveraging public-private partnerships and green bonds to finance large-scale fleet transitions. –Enhancing collaboration among airports, operators and energy providers to share best practices and accelerate innovation. The paper concludes that decarbonizing bus operations is both technically feasible and economically advantageous, positioning airports as enablers in the broader energy transition of the aviation industry. By adopting a tailored, evidence- based approach, airports can also enhance operational efficiency while contributing meaningfully to the aviation industry’s net-zero journey.Decarbonizing Aviation Ground Operations: Alternative Bus TechnologiesNovember 2025 Total cost of ownership analysis is a pragmatic tool to empower airports to advance strategic decisions on net-zero ground operations. Decarbonizing Aviation Ground Operations: Alternative Bus Technologies 3

Decarbonizing Aviation Ground Operations 2025