The A-4 Skyhawk flew more missions in Vietnam than any other naval aircraft. Developed in the mid-1950s by Douglas, the A-4 could carry a maximum payload of 8,200 pounds and a functional payload of 5,000 pounds. Its maximum speed was 685 mph and it had a range of 700 miles. Its built-in armament consisted of two 20mm cannons. The A-4 Skyhawk was propelled by either a 7,700-pound thrust Wright J65 engine or an 8,500-pound thrust Pratt and Whitney J52 engine.