Andrew Blum in WIRED:
…More than 2 million flights pass over the city every year, most traveling to and from the metropolitan area’s three busiest airports: John F. Kennedy, Newark, and LaGuardia. And all that traffic squeezes through a network of aerial routes first laid out for the mail planes of the 1920s. Aircraft are tracked by antiquated, ground-based radar and guided by verbal instructions issued over simplex radios, technology that predates the pocket calculator. The system is extremely safe–no commercial flight has been in a midair collision over the US in 22 years–but, because the Federal Aviation Administration treats each plane as if it were a 2,000-foot-tall, 6- by 6-mile block lumbering through the troposphere, New York is running out of air.
This is a nightmare for New York travelers; delays affect about a third of the area’s flights. The problem also ripples out to create a bigger logjam: Because so many aircraft pass through New York’s airspace, three-quarters of all holdups nationwide can be traced back to that tangled swath of East Coast sky….