DENVER, CO - JULY 14: An air traffic controller monitors flights while working in the Terminal Radar Approach Control center on July 14, 2011 at the Denver International Airport in Denver, Colorado. The Federal Aviation Administration (FAA), is marking 75 years of federal air traffic control in the United States today. Beginning with just 15 employees in 1936, the FAA now has some 15,000 air traffic controllers and technicians working nationwide. In 2010, the Denver International Airport was the 4th busiest airport in the world, with some 650,000 flights per year and 52 million passengers passing through the airport. (Photo by John Moore/Getty Images)
