On a bluff near St George, Utah, this concrete arrow remains from the Commerce Department’s Transcontinental Airway System, a chain of beacons built in 1923 to guide airmail pilots. Clouds and fog rendered them useless. One mail pilot was forced by bad weather to parachute out of two airplanes in two months in the fall of 1926 (after one jump in training and another as a test pilot). Undeterred by this, the pilot—a Minnesota politician’s kid named Charles Lindbergh—continued his flying career with some success.