This course addresses the architecting of air transportation systems. The focus is on the conceptual phase of product definition, including technical, economic, market, environmental, regulatory, legal, manufacturing, and societal factors. It centers on a realistic system case study and includes a number of lectures from industry and government. Past examples include: the Very Large Transport Aircraft, a Supersonic Business Jet, and a Next Generation Cargo System. The course identifies the critical system level issues and analyzes them in depth via student team projects and individual assignments. The overall goal of the semester is to produce a business plan and a system specifications document that can be used to assess candidate systems.