312th Special Mission Squadron
The 312th Special Mission Squadron was activated at Nha Trang air base on 1 August 1951. It moved to Tan Son Nhut in 1952. It is not exactly known what types of aircraft were operated by the 312th SMS, but at least two Republic RC-3 Seabees, the presence of which at the time initiated never-persued plans to comission amphibian squadrons within the VNAF, were used by the 312th SMS for patrol flights in the Delta region. Additional info can be found at the Seabee page. The VNAF's Beech D18Ss and Marcel-Dassault Flamants were most likely operated by the 312th SMS too.314th Special Mission Squadron
The 314th Special Mission squadron was formed at Tan Son Nhut in the 1960s. It operated U-6A Beavers, C-47D Dakotas and unknown other types. The 314th was also responsible for flying and maintaining the Air Vietnam fleet of airliners. It was quite common that pilots flew combat missions one day, and take a civil passenger DC-6 to Bangkok the next.