Excerpt taken from the National Postal Museum website:
Quote:
On January 6, 1947, the first experimental helicopter flights were made in the New York City area. Nine helicopters were used for the tests, landing and taking off from thirty-nine sites in New York, New Jersey and Connecticut. In the first day of operation of the experimental service, over 100,000 letters (mostly philatelic collector's items) were carried by helicopter service. In a display of the community excitement over the prospective service, an article in the New York Times noted that crowds meeting the helicopters included "many boys and girls excused from school for the occasion."
Among the aircraft used in the New York experimental flights were the Sikorsky S-51, Firestone XR-9B, and Bell Aircraft B-47 helicopters. United Air Lines was the first scheduled airline to experiment with helicopter service, using a Sikorsky aircraft to carry passengers and mail in the Chicago area. By 1953, helicopters were beginning to experiment with nightly airmail service. On April 8, 1953 a helicopter flew 700 pounds of airmail from La Guardia Airport and Bridgeport, Connecticut between 4:25 a.m. and 5:05 a.m.