Appendix 2: Assumptions for each scenario Table 1 in the paper presents the general assumptions that apply across all three technologies. These include variables such as average fleet size, range, utilization rate, expected vehicle lifespan and discount rate. Table 2 below summarizes technology-specific cost and performance assumptions, such as refuelling times, charging infrastructure requirements and battery replacement cycles. The TCO model created for this analysis is available on demand, and all sources are described in detail (including all average assumptions where sensitive data applies). This model can be adapted for different regions and operational contexts. Baseline parameters by bus technology TABLE 2 Baseline parameters Parameter Value CommentDiesel busesAverage bus price (€/bus) 259,000 Based on an average of six different bus models Maintenance cost (€/km) 0.61 Average of three independent sources Energy consumption (l/km) 0.34 Based on an average of seven bus models Diesel price (€/l) 1.67 Average retail price across 10 European countries Lifespan (years) 15 Various sources Salvage value (% of purchase price) 15 - Driver training cost (€) 0 No additional training required Insurance cost (€) 0 Assumed to be self-insured Registration cost (€) 0 Assumed that no registration fees apply Government subsidy (% of purchase price) 0 No subsides for diesel busesElectric and retrofitted busesAverage bus price (€/bus)* 550,000 (electric) retrofitted bus, approximately 50% of new electric bus Average of five electric buses Capex learning rate (%/year) 3.9 Reduction expected as battery technology scales Maintenance cost (€/km)* 0.37/0.40 Electric/retrofitted, excluding battery costs Energy consumption (kWh/km) 1.15 Average of seven different buses Electricity price (€/kWh) 0.12 Validated with stakeholders Battery replacement frequency (years) 9 Validated with stakeholders Battery replacement cost (% of new e-bus) 35 Based on multiple sources and stakeholder input Battery size (kWh) 386 Average of six different buses Bus-to-charger ratio 2:1 One charger for two buses; validated with stakeholders Bus output power (kW) 150 Two sockets per charger; one socket per bus Charger efficiency (%) 95 Typical market average; input power reduced to 143 kW Decarbonizing Aviation Ground Operations: Alternative Bus Technologies 27

Decarbonizing Aviation Ground Operations 2025