Even if aviation only accounts for 2 % of global energy-related CO2 emissions, but it is the most challenging sector to decarbonize. As aviation demand grows and the need for sustainable jet fuels becomes urgent, green hydrogen could substitute conventional fossil fuels, thereby enabling carbon-free flights. This study investigates a techno-economic analysis of on-site versus off-site green hydrogen supply chains. A case study at the ToulouseBlagnac airport (Europe's first station for the production and distribution of renewable hydrogen) in France is developed to meet commercial aviation's hydrogen fuel demand between 2025 and 2050. Demand of hydrogen is projected based on the trend of jet fuel consumption. First, the cost of solar-based renewable electricity is estimated at the two green hydrogen production sites using levelized cost of electricity production. Second, levelized cost of hydrogen (LCOH) is evaluated for three value chain scenarios: one on-site (Toulouse airport) and two off-site (Marseille) for gaseous and cryogenic transportation of liquid hydrogen (LH2). A relative cost advantage is shown for the off-site case with cryogenic truck transportation at LCOH of <euro>9.43/kg.LH2. This study also reveals the importance of electricity price, investment costs, operation costs, economies of scale, and transportation distance in different scenarios.