An accident that occurred in the skies over the Grand Canyon in 1956 resulted in the establishment of the Federal Aviation Administration （FAA）to regulate and oversee the operation of aircraft in the skies over the United States， which were becoming quite congested. The resulting structure of air traffic control has greatly increased the safety of flight in the United States， and similar air traffic control procedures are also in place over much of the rest of the world. Rudimentary air traffic control （ATC） existed well before the Grand Canyon disaster.As early as the 1920s， the earliest air traffic controllers manually guided aircraft in the vicinity of the airports， using lights and flags， while beacons and flashing light swere placed along cross-country routes to establish the earliest airways. However，this purely visual system was useless in bad weather， and， by the 1930s， radio communication was coming into use for ATC. The first region to have some thing approximating todays ATC was New York City， with other major metropolitan are as following soon after.
　　In the 1940s， ATC centres could and did take advantage of the newly developed radar and improved radio communication brought about by the Second World War，but the system remained rudimentary. It was only after the creation of the FAA that fullscale regulation of Americas airspace took place， and this was fortuitous， for the advent of the jet engine suddenly resulted in a large number of very fast planes，reducing pilots margin of error and practically demanding some set of rules to keep everyone well separated and operating safely in the air.
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