No known major achievements

The A340 was designed in parallel with the twin-engined A330: both aircraft share the same wing and similar fuselage structure, and borrow heavily from the advanced avionics and composite structure technology developed for the A320.

Both the A330 and A340 are assembled on the same final assembly line at Toulouse-Blagnac, France. The four-engined A340 is able to fly long over-water routes. Because of its ETOPS immunity, Virgin Atlantic Airways used the motto "4 Engines 4 Long Haul" on its A340 fleet.

The A340 was originally intended to use the new superfan engines of International Aero Engines, but they decided to stop the engine's development. The engine nacelles of the superfan engine consisted of provisions to allow a large fan near the rear of the engine. As a result of the superfan cancellation by IAE, the CFM International CFM56-5C4 was used as the sole engine choice instead of being an alternate choice as originally envisioned. The longer-range versions, the A340-500 and -600, are powered by Rolls-Royce Trent 500 engines.

When the A340 first flew in 1991, engineers noticed that the wings were not strong enough to carry the outboard engines at cruising speed without warping and fluttering. To alleviate this, an underwing bulge called a plastron was developed to correct airflow problems around the engine pylons and to add stiffness. The modified A340 began commercial service in 1993 with Lufthansa and Air France.

The A340 incorporates high-technology features such as fully digital fly-by-wire flight control system. It also uses joysticks instead of yokes, with one joystick to the left of the pilot and one to the right of the co-pilot. The A340's flight deck is highly similar to the A320's, and employs a common pilot rating with the A330. This enables A330/A340 flight crews to fly A320s and vice-versa with minimal extra training. This saves costs for airlines that operate both aircraft families. The cockpit also features CRT-based glass cockpit displays on the A340-200 and A340-300 and LCD-based on -500 and -600. Some composite primary structures are also used.

An A340 was used as first commercial jet that enables the use of mobile phones during flight. In March 2008 Emirates Airlines introduced a system allowing passengers to make outgoing calls with their handset. Incoming calls are not possible and the system is not available at night or during landing and take-off.

The first published studies for the A340 were as the TA11 in 1981, as shown in the November issue of Air International Magazine (coinciding with the display of the A300 at that year's Farnborough Airshow). Concept drawings of the A320 (SA 9) and A330 were also published, along with estimated performance figures by Airbus Industrie.

The A340 was launched in June 1987 as a long-range complement to the short-range A320 and the medium-range A300. At the time, Airbus's twinjets were at a disadvantage against aircraft such as the Boeing 747 because of the ETOPS problem as defined by the then-current regulations: two-engined aircraft had to stay within 60 minutes' flying distance of a suitable diversion airport, which prevented them from competing on long over water routes. Furthermore, the existing ETOPS immune wide-bodies in the 250-300 seat range, the trijet DC-10 and L-1011, were aging, as they had been in service since the early 1970s.