this document, it shows that as early as 1959, the Joint Chiefs of Staff had conceived a plan for U.S. military intervention in Laos, two years earlier than previously thought. In fall 1959, the U.S. Special Forces initiated training a number of Laotian soldiers in unconventional warfare tactics under the codename Erawan. This development occurred due to the US being unable to integrate the Pathet Lao communist army with the royal army. Air America—the name changed on March 26, 1959, primarily to avoid confusion about the air proprietary's operations in Japan 16—provided essential transportation for the expanding American effort in Laos. Since the Laotian government wanted U.S. assistance to remain secret in the Laotian Civil War against the Pathet Lao, the CIA established a unit from the United States Army Special Forces who arrived on the CIA proprietary airline Air America, wearing civilian clothes and having no obvious U.S. connection. These soldiers led Meo and Hmong tribesmen against communist forces. The covert program was called Operation Hotfoot. At the U.S. Embassy, Brigader General John Heintges was labeled the head of the "Program Evaluation Office". During the summer of 1959, North Vietnam invaded Laos, which made the U.S. believe that its chances of success became even lower. They believed that the anti-Pathet policies had little chance of success due to the invasion. The U.S. Special Forces Group, code-named Hotfoot under the command of Lieutenant Colonel Arthur "Bull" Simons, penetrated Laos. Twelve Mobile Training Teams took up duties in Vientiane, Luang Prabang, Savannakhet, and Pakse. CIA officials in Laos had requested additional air transport resources. The CIA, in August 1959, directed CIA proprietary Air America to train two helicopter pilots. Further, Air America directed search and rescue missions in Laos in addition to its role in combat operations. Originally posted as a short-term requirement, this operation served as the beginning of a significant rotary-wing operation in Laos. Vang Pao expressed concerns that the Hmong were likely to suffer reprisals from communists. With assistance from a U.S. Special Forces team, he began to organize a Hmong stay-behind force. Declassified documents from 2008 also revealed that the U.S. ambassador in Laos at the time served as the field commander of the so-called "secret war" there. Outside of just training locals, previously secret U.S. Air Force official histories of the Vietnam war were published in April 2008 by the National Security Archive which disclosed for