http://news.yahoo.com/news?tmpl=stor...t_050121003248
The Federal Aviation Administration is doubling the airspace routes between 29,000 feet (8,839 meters) and 41,000 feet (12,496 meters) by spacing aircraft a thousand feet (304 meters) apart instead of 2,000," the regulator said.
It said the reform gives air traffic controllers more choices so that aircraft can fly more direct routes at the most fuel-efficient altitudes.
The agency said the procedure -- known formally as Reduced Vertical Separation Minimum -- will work safely because most jets are now equipped with more advanced flight systems.
The horizontal separation of aircraft at high altitudes remains at five miles (eight kilometers).