2 # 704 , 1 # 705 and 2 # 706 , Washinton Bicentennial , on this US Contract Air Mail Route No 18 North , AM18 - POD , First Flight Cover , FFC . Pilot - R P Craine . Machine cancellation Jan 16 , 1932 , 2:30 PM , Sioux Falls , SOUTH DAKOTA . American Air Mail Society Catalogue , AAMS , # 18N21 , Type 18c green cachet . First Flight Air Mail Route AM18 POD , Sioux Falls South Dakota , January 16 , 1932 . Plane over waterfall . Addressed To : J W Fox , 640 So Main Ave , Sioux Falls , So Dak . Via Watertown So Dak .
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