Introduction The aviation industry is committed to achieving net-zero emissions by 2050, with every actor – airlines, airports, ground handling companies and passengers – playing a critical role in this transition. As global air passenger numbers are projected to grow at a compounded annual growth rate (CAGR) of 3.6%, by 2050,1 airports worldwide will expand rapidly, especially in emerging markets. Major projects such as the Al Maktoum International Airport in Dubai, King Salman International Airport in Saudi Arabia and Istanbul airport in Türkiye are set to accommodate hundreds of millions of new passengers annually, while new terminals and expansions in Asia and Europe further underscore this growth. This surge in passenger demand is driving significant airport infrastructure investment, including the transformation of ground operations. Promising technologies for flight operations – such as sustainable aviation fuels (SAF) and novel propulsion aircraft (hydrogen and battery- electric) – are advancing quickly, requiring parallel upgrades in airport infrastructure. While these technologies primarily address Scope 3 emissions (which typically account for over 90% of an airport’s emissions profile), there is also a growing focus on reducing Scope 1 and Scope 2 emissions from buildings, vehicles and ground operations. Trialling on-the-ground decarbonization initiatives can also pave the way for battery-electric and hydrogen aviation, offering a practical means to test, adapt and build familiarity with the technologies that may eventually power aircraft. Airports serve as strategic nexuses not only for aviation but also for the industries and communities around them. Infrastructure changes required for decarbonization may benefit a wider set of stakeholders, making airport master planning increasingly important for both aviation and potential future offtakers who could leverage the airport’s energy transition. This broader approach can strengthen the business case for infrastructure upgrades. This paper provides a practical tool for airports at this transition point, focusing on a key use case: airport bus operations. Converting bus fleets is a tangible and impactful way to reduce Scope 1 emissions, with many airports already piloting or transitioning to new power trains. The airport bus market itself is undergoing rapid transformation; valued at $15.12 billion in 2024, it is projected to grow at a CAGR of 11.6% to reach $44.35 billion by 2033. Europe is expected to account for over 37.8% of this market, driven by stringent environmental regulations and strong government support for electric and hybrid buses. The analysis in this paper covers the main technology options for airport buses that could reduce or eliminate tailpipe emissions: retrofitted diesel buses, battery-electric buses and hydrogen fuel cell buses. It compares the TCO and technical feasibility of each option, while recognizing that different airport archetypes, geographies, operations and ownership models will ultimately affect the feasibility and costs of new technology deployment. Other technologies, such as hydrogen internal combustion engines (ICE), fossil fuel- biofuel blends and natural gas or biomethane buses, are not included in the quantitative analysis but are considered qualitatively in the technology alternatives discussion. Decarbonizing Aviation Ground Operations: Alternative Bus Technologies 4

Decarbonizing Aviation Ground Operations 2025