This report identifies planning process options, funding challenges, and potential actions to improve integration of rail services with airports, particularly in congested corridors. The report identifies the challenges involved in a variety of institutional settings in different regions and develops ways to better integrate inter-agency planning processes. It identifies specific site planning and service coordination actions to promote air rail transfers, defines the data and analysis capabilities needed to determine the feasibility and effectiveness of improved integration of air and rail services, and demonstrates the application of methods and tools to support integrated planning for air and rail services and decision making. Key issues covered include rail and air in a competitive and complimentary mode. The report has an accompanying CD-ROM (CRP-CD-157) that includes an Air/Rail Diversion model, a sketch planning tool capable of supporting the evaluation of a range of policy actions that affect choice of air or rail for long distance travel. A User Guide provides direction in applying the model to evaluate different scenarios and a Technical Appendix provides supplemental information for the model. The report and accompanying tool will be of interest to airport and rail operators, state and regional transportation planners, and other interested stakeholders.