Railways and aviation are major modes of international origin–destination (OD) travel, and the intermodal model is influenced by external factors such as the layout of airports and train stations, as well as passenger demands and preferences. At the same time, internal factors like infrastructure, service protocols, and coordination mechanisms also impose constraints. This study focuses on the passenger transfer process, luggage handling procedures, and ticketing mechanisms in air-rail intermodality, systematically identifying the factors that affect air-rail intermodal services from the perspective of passenger preferences throughout the “end-to-end” travel process. Using international air-rail intermodality in cities such as Guangzhou, Hangzhou, and Tianjin as case studies, the research analyzes the key service metrics that passengers prioritize in air-rail intermodal travel and establishes a correlation mechanism between service components and these metrics. A SWOT analysis is employed to summarize the strengths and weaknesses of various air-rail intermodal models, identify the bottlenecks and challenges in air-rail intermodal cooperation, and propose development strategies for air-rail services through the application of new technologies, product optimization, and infrastructure improvements. The study finds that business travelers prioritize convenience, while leisure travelers focus more on affordability. Despite regional differences in international air-rail intermodal services, common challenges persist, including insufficient cooperation among operators, a lack of service refinement, and increasing infrastructure demands, often accompanied by high construction costs. In air-rail services with spatial separation between airports and stations, particular emphasis should be placed on transfer connectivity, especially in developing luggage and check-in facilities before transfers, which plays a crucial role in managing seasonal surges in passenger volume. For air-rail services where airports and stations are in close proximity, optimizing the coordination of air and rail timetables holds significant potential, requiring personalized ticketing solutions tailored to different passenger groups. Integrated air-rail intermodal services should prioritize enhancing “soft power,” not only by offering flexible, personalized services but also by improving the overall service level through specialized third-party intermodal platforms and collaborative mechanisms.