The Douglas A-4 Skyhawk is a carrier-capable attack aircraft developed for the United States Navy and United States Marine Corps. The delta winged, single-engined Skyhawk was designed and produced by Douglas Aircraft Company, and later by McDonnell Douglas. It was originally designated the A4D under the U.S. Navy's pre-1962 designation system.
The Argentine Naval Aviation also bought the Skyhawk known as A-4Q in the form of 16 A-4Bs plus two for spare parts, modified with five weapon pylons and to carry AIM-9B Sidewinders. They were received in 1971 to replace Grumman F9F Panther and Grumman F9F Cougar in use from the aircraft carrier ARA Veinticinco de Mayo by the 3rd Fighter/Attack Squadron (Spanish: 3ra Escuadrilla Aeronaval de Caza y Ataque).
http://en.wikipedia.org/wiki/A-4M_Skyhawk