The first VNAF B-57 crews began training in secret with 405th aircraft at Clark AB later in 1964. One of the students was none other than Nguyen Cao Ky, the commander of the VNAF and later president of the Republic of Vietnam. As the crews completed their training at Clark, they went to Da Nang Air Base and flew combat missions with the 405th's 8th or 13th Bombardment Squadrons, whichever happened to be on station at the time. To gain combat experience, each new crewmember flew with an American pilot or navigator, whichever the case may be. Eventually, the VNAF crew members flew in VNAF-marked B-57s, but their combat missions always remained strictly under USAF operational control.