The A-4 owes its origins to a desire expressed by the US Navy for a replacement of the A-1 Skyraider The engineering design genius Ed Heinemann created a super lightweight & simple airplane which was pressed into service on American aircraft carriers in 1956 The E of which 499 were made & F of which 147 were made represent the first real upgrade in airplanes with a more potent engine two extra mooring towers for cargo for a total of five & enhanced avionics They were used extensively & with excellent results during America s war in Vietnam