Airmail Envelope (c. 1930) depicting a unique mail transfer system for picking up mail by Pitcairn Post Office at Bohinski Field in Monroeville. The aerial pick-up system was devised by Dr. Lytle S. Adams of Irwin, Pa. Dr. Adams realized that the problem with airmail delivery to small towns like Irwin was the long delay occasioned by take-offs and landings. He invented a system like that used by trains that picked up mail on the run, wherein the mail bag suspended from two 40-foot poles so that a low-flying plane could snag the mail bag with a hanging hook. This system was so successful it was widely used in the tri-state area, and became a common practice at hundreds of small town airports.
