Aviation industry leaders believed the airplane could not reach its full commercial potential without federal action to improve and maintain safety standards. At their urging, the Air Commerce Act was passed in 1926. This landmark legislation charged the Secretary of Commerce with fostering air commerce, issuing and enforcing air traffic rules, licensing pilots, certifying aircraft, establishing airways, and operating and maintaining aids to air navigation. A new Aeronautics Branch in the Department of Commerce assumed primary responsibility for aviation oversight, and William P. MacCracken, Jr., became its first director.

In 1934, the Department of Commerce renamed the Aeronautics Branch the Bureau of Air Commerce to reflect the growing importance of aviation to the nation. In one of its first acts, the Bureau encouraged a group of airlines to establish the first air traffic control centers (Newark, New Jersey; Cleveland, Ohio; and Chicago, Illinois) to provide en route air traffic control. In 1936, the Bureau took over these centers. Early en route controllers tracked the position of planes using maps and blackboards and little boat-shaped weights that came to be called “shrimp boats.” They had no direct radio link with aircraft, but used telephones to stay in touch with airline dispatchers, airway radio operators, and airport traffic controllers. Although en route ATC became a federal responsibility, local government authorities continued to operate …..