To support the Hmong’s guerrilla tactics against the Lao Viet, the idea of air interdiction was introduced in early 1964. However, the main problem was the lack of pilots and airplanes in the Royal Lao Air Force (RLAF). Although the United States could happily supply the planes to the RLAF, it would be too risky to put American pilots on those planes and fly on a regular basis, as this was a stark violation of the Geneva Accords. Project Water Pump was then established to train Lao pilots at Udorn RTAF base from March 1964.53 The Americans then came up with the idea of using Thai RTAF pilots for air interdiction in Laos, while the Lao pilots were being trained.5