The Next Generation Air Transportation System (NextGen) is the Federal Aviation Administration (FAA) plan to modernise the National Airspace System (NAS) through to the year 2025. The Next Generation Air Transportation initiative started in 2003 to transform the U.S. air transportation system by 2025. In contrast to today's system, the Next Generation Air Transportation System will be more flexible, resilient, scalable, adaptive, and highly automated - meeting up to two to three times current demand while reducing environmental impacts. NextGen integrates new and existing technologies, policies and procedures to reduce delays, save fuel and lower aircraft exhaust emissions to deliver a more reliable travel experience. NextGen includes security, safety, and efficiency of passenger, cargo, and aircraft operations. NextGen's computerised air transportation network will stress adaptability by enabling aircraft to immediately adjust to ever-changing factors such as: weather, traffic congestion, aircraft position via GPS, flight trajectory patterns, and security issues.