The U.S. aviation industry, airline passengers, aircraft pilots, airports, and airline companies are all facing challenges. The air transportation system is experiencing unprecedented and increasing levels of use. The federal government understands the critical need to update the U.S. air transportation system, and plans to implement the Next Generation Air Transportation System (NextGen) by 2025. This system is an example of active networking technology that updates itself with real-time shared information and tailors itself to the individual needs of all U.S. aircraft, stressing adaptability by enabling aircraft to immediately adjust to ever-changing factors. On April 1-2, 2008, a workshop was held at the National Academies to gather reactions to the research and development aspects of the Joint Planning and Development Office's baseline Integrated Work Plan (IWP), which is designed to increase the efficiency of airport and air space use in the United States. This book provides a summary of the workshop, which included presentations on the following topics: Airport operations and support; Environmental management; Air navigation operations, Air navigation support, and flight operation support; Positioning, navigation, and timing services and surveillance; Weather information services; Safety management; Net-centric infrastructure services and operations; and Layered adaptive security.