Douglas Aircrafts El Segundo plant was awarded the prototype contract for a new tactical attack jet for the U.S. Navy and the Marine Corps in 1952 after chief engineer Ed Heinemann had convinced the Bureau of Aeronautics his design would meet the challenging specification and yet weight just half the suggested 30,000 lb (13,607 kg). The prototype flew in June 1954 and not only fully met the requirements but set a world speed record and proved such a good basis for improvement that the A-4 remained in production for 26 years.
The requirements were based on Korean experience and called for the maximum payload/range and equipment for carrier operation, but not for all weather avionics. The A-4 bristled with novel features intended to reduce weight and complexity. The main gears, tall enough for large under wing clearance, fold forward to lie under the main wing box without cutting into it.
The wing is a curved-tip delta so small it does not need to fold, the entire box being an integral tank and the leading edges having full span slats. The cockpit was put high above the nose for good view, and in the final versions the canopy was enlarged. There are large airbrakes on the rear fuselage, flight controls are powered, and the unique rudder hastily redesigned to eliminate 'Buzz' by having a single skin on the centerline with ribs on the outside remained in production to the 2,960th and last aircraft in 1980.