The aircraft that was ultimately to become the A-1 Skyraider was first produced by Douglas Aircraft Company in 1944. This aircraft, the BT2D-1 was conceived by Douglas Aircraft master designer Edward Heinemann. The Skyraider name and redesignation as the AD-1 occurred in 1946. The Skyraider production run of 3,180 culminated with the last AD-7 (A-1J) rolling off the Douglas assembly line in February, 1957. In between, came no fewer than 17 different variants which were optimized for a wide variety of roles such as day and night attack, airborne early warning, electronic countermeasures, anti-submarine patrol, VIP transport, target tow, air ambulance, and photo reconnaissance. Those interested in a more detailed Skyraider history should consult one of several reference books on the Douglas Skyraider. Also, you can get additional history on the Douglas Skyraider at The-Hangar.
The AD designation for the Skyraider was changed in 1962 to A-1. The AD-5 became the A-1E, the AD-5N became A-1G, the AD-6 became the A-1H, and the AD-7 became the A-1J. These four models of the A-1 (E/G/H/J) were the ones I flew during my one year combat tour from October 1971 to October 1972. In December of 1972, all remaining A-1s were handed over to the VNAF and the 1st SOS ceased combat operations in SEA.