In 1921, army navigational beacons between Columbus and Dayton, Ohio, guided pilots at night. The Post Office took over the system in 1922 and by the end of 1923, had constructed similar beacons between Chicago, Illinois and Cheyenne, Wyoming. Each beacon, erected at about 10 miles intervals, was topped with a rotating light visible up to 40 miles away. Green lights signaled airfields were near. A red light meant no airfield was handy. The first regularly scheduled night service was inaugurated on July 1, 1924. By the end of the year, beacons lit the skies from Rock Springs, Wyoming to Cleveland, Ohio. The Commerce Department took over the system in 1927. The beacons were retired in the 1950s as better-equipped airplanes made such navigational aids unnecessary.
(On loan from the National Air and Space Museum.)
Narrator: How do you suppose the early airmail pilots flew at night?
At first, all pilots flew by day
but the post office had to fly planes at night in order to make airmail service work.
Their solution is just above your head.
Do you see the beacon light near the de Havilland's tail wing?
The post office built a series of beacons like this one on towers spaced ten miles apart
along a flyway from New York to California.
They safely lit the way for the early airmail flyers.