NPR: “The radar system used to guide U.S. flights is more than 40 years old, which may help explain why nearly one-quarter of all those flights are late. The Federal Aviation Administration wants to phase out radar and roll out a satellite-based air traffic control system, NextGen, which is based on the same GPS technology now used in cars. Air traffic controllers and pilots would have instantaneous information on the location of any plane at any time. Supporters of the system say it would allow planes to fly closer together, making more room in the sky for additional flights and cutting delays. But it will cost the government as much as $20 billion to update its air traffic control operations, and the airline industry will have to spend another $20 billion for new equipment and training.”