On April 15, 1926, 24-year old Charles A. Lindbergh, Chief Pilot for Robertson Aircraft Corporation, took off from Chicago’s Maywood Airfield in a WWI DH4 mail plane bound for St. Louis. It was the first flight of Contract Air Mail Route 2, connecting St. Louis with the Post Office’s transcontinental air mail service at Chicago.

During the spring and summer months Lindbergh and his fellow Robertson pilots completed 99% of their flights, but fall brought longer nights, worse weather, and greater challenges. In September, Lindbergh found himself above a solid fog bank at night between Peoria and Chicago. Unable to find Maywood Airfield, his fuel ran out, and he took to his parachute. He landed in a corn field and, assisted by local farmers, located the wreckage and delivered the mail bags to the nearest post office.

Two months later Lindbergh encountered low ceilings, thick clouds, snow and fog, and with gas running short, he attempted without success to climb above the clouds. When his tank went dry, he bailed out again. This time he landed on a barbed wire fence, soaked with rain and snow. Undaunted, he returned the next morning in another Robertson plane, found the wreckage, retrieved the mail bags, and flew them on to Chicago.

While flying the mail Lindbergh decided to seek the Orteig Prize for the first non-stop flight between New York and Paris, and left Robertson to pursue that dream. Lindbergh hoped that the Paris flight would arouse interest in aviation and demonstrate its capabilities of modern equipment, and succeeded beyond his wildest dreams. Yet the hazards remained daunting.

Airplanes at that time lacked instruments to fly in clouds, and night flight added danger and difficulty. Because a pilot’s senses were misleading, “seat of the pants” flying led to loss of control.

Transcontinental Air Transport (TAT), formed to provide regular coast-to-coast service, carried its passengers by rail at night. Safe travel by air was impossible until these obstacles were overcome. But Lindbergh’s Paris flight accelerated efforts to solve these problems, and in 1929 a breakthrough occurred. Famed racing pilot (and MIT Ph.D.) Jimmy Doolittle took off, flew a fifteen mile course, and landed solely by instruments, with no vision outside the cockpit. Three recent innovations made this achievement possible.

The first was the gyroscopic artificial horizon, which allowed the pilot to maintain control without seeing outside. The second was the sensitive altimeter, which accurately showed the airplane’s altitude to within 10 feet. The third was radio beacons and radio ranges, which permitted navigation without ground reference. These technological developments solved the problems of blind flight and night flight, and sparked a revolution in air transport.

TAT reorganized as Transcontinental and Western Airlines (TWA) in 1930. It eliminated the rail connections and reduced coast-to-coast travel time from 48 hours to 36. The City of St. Louis hired the first air traffic controller to handle the growing volume of air traffic in the area. He progressed from using flags to lights to radio to communicate with airplanes flying to and from the airport. Other cities followed suit.

In 1934 TWA introduced the DC-2, a 14-passenger airliner that cut the coast-to-coast flight time to 18 hours. Two years later American Airlines followed with the 21-seat DC-3, the first plane capable of profitable passenger operation. As air travel grew in popularity and aircraft performance increased during the 1930s, the need for control en route as well as in the vicinity of airports became evident. The airlines created the first airway traffic control station at Newark in 1935, and in 1936 the federal government took over operation of the Newark facility and others at Chicago and Cleveland. By 1941 24 air traffic control centers were overseeing air traffic flying a nationwide airway network, in all weather.

WWII brought radar, the Instrument Landing System, and improved radio communications and navigation aids. By the 1960s, some airliners could land without the pilot touching the controls, and air travel had become by far the safest form of transportation. In the 21st century, air traffic control will transition from a ground-based to a satellite-based system known as NextGen to further enhance safety, reduce delays, and save time and fuel.

The Robertson air mail service between Chicago and St. Louis was the earliest predecessor of American Airlines, the world’s largest air carrier. In 2016 passengers still board American planes to fly the air route pioneered by Charles Lindbergh ninety years ago.