The F-4 Phantom was probably the most ubiquitous and the most successful combat aircraft in the Southeast Asian theatre.  Originally designed for the US Navy the aircraft was also used extensively by the Air Force and the Marine Corps and was exported to 11 nations worldwide.  The Phantom was a truly multi-role aircraft being equally capable of air-to-air and air-to-ground missions.  Its sturdy airframe enabled it to carry up to 22,500lbs of stores including just about every bomb in the US inventory together with AIM-7 Sparrow and AIM-9 Sidewinder air-to-air-missiles.  One of its few limitations was the lack of an internal gun.  The Phantom was designed when the advent of the air-to-air missile was thought to be the complete answer to air combat.  As a fighter the aircraft’s intended role was as a bomber destroyer and the target could be more easily killed with a missile than a gun.  Any thought of the return to dogfighting as in World War II or Korea was dismissed.  However, the value of a gun soon became apparent in Vietnam and the Phantom could be fitted with externally mounted gun pods but these were heavy and caused drag that slowed the aircraft down considerably.  Only when the F-4E version of the Phantom entered service in Southeast Asia in November 1968 was this deficiency remedied.  However, despite the omission of a gun the Phantom proved to be one of the truly great aircraft of the 1960s and 1970s and it played a major role in the air war in Southeast Asia.  The first Phantoms to enter action were Navy F-4Bs operating on board the USS Constellation, Ranger and Coral Sea in 1964.