In 1929, Archie W. League, a pilot and mechanic, was hired as the first US air traffic controller. League’s control tower was far less complicated than today’s standards. Every day, League would carry a chair, umbrella, lunch, water, notepad, and signal flags in a wheelbarrow to an airfield in St. Louis and guide pilots on departures and landings.
He had two flags, one for ‘Go’ and the other for ‘Hold,’ and this was the first coordinated air traffic control.
He is generally acknowledged as the world’s first Air Traffic Controller.