The MB-339 is of conventional configuration, and shares much of the 326's airframe. It has a low, un-swept wing with tip tanks and jet intakes in the roots, tricycle undercarriage, and accommodation for the student and instructor in tandem. The most significant revision was a redesign of the forward fuselage to raise the instructor's seat to allow visibility over and past the student pilot's head.
The first flight took place on August 12, 1976 and deliveries to the Italian Air Force commenced in 1979. Still in production in 2004 in an enhanced version with a much-modernised cockpit. Over 200 MB-339s have been built, with roughly half of them going to the Italian Air Force.
The Lockheed-Aermacchi MB-339 T-Bird II was a losing contender in the USA's Joint Primary Aircraft Training System (JPATS) aircraft selection. Among the seven to enter, the Raytheon/Pilatus entry won, which became the T-6 Texan II.
According to an article posted on the Italian website 'Il Porto Franci', called 'Armi e finanziamenti nel corno d'Africa', Eritrea paid about $US 50 million for six MB-339 CE's in 1997. This is the original MB-339 with more advanced avionics for the ground attack role, RWR, uprated Viper 680-43 engine, and larger wingtip tanks. It is said to be capable of carrying Sidewinder AAM's, AGM-65 Maverick AGM's, and laser guided bombs. Unit price of the MB-339C would have to be somewhere around $US 8.3 million in 1997 dollars.
Argentine Navy (Comando de Aviación Naval) was the first foreign user of the forerunner MB-326GB, buying eight in 1969. Ten MB-339s arrived in 1979 and were the only attack jets to operate from Port Stanley Airport (along with turboprops FMA IA 58 Pucarás and T-34 Mentors) during the Falklands War in 1982. On May 21 during a routine reconnaissance flight and flown by Lieutenant Crippa, a MB-339 was the first one to attack the Royal Navy amphibious force hitting HMS Argonaut. Five airframes were captured or destroyed by the British. 11 surplus Brazilian Air ForceMB-326GC were delivered after the war and are still in service and they are locally known as MC-32.
Up to 1,800 kg (4,000 lb) of weapons on six hardpoints, including AIM-9 AAMs, AGM-65 AGMs, Marte ASMs, gunpods, bombs, and rockets. (option for two 7.62mm miniguns or two 30mm DEFA cannon in MB-339CD)