http://en.wikipedia.org/wiki/Pope_Field



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After coordinating with the South Vietnamese Government, the Americans turned to action in November 1961, when 6 C-123 Provider transports, specially modified for aerial-spraying operations, left Pope Air Force Base, North Carolina, en route to South Vietnam. Although earlier small-scale defoliation experiments had been conducted in Vietnam with both C-47 transports and H-34 helicopters, the decision to go to the more modern C-123 as the primary defoliant aircraft proved an excellent choice.
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http://www.globalsecurity.org/military/systems/aircraft/uc-123.htm