The Airbus A340 family was developed simultaneously with the twin-engined A330. Therefore except for the number of engines, they are very similar in appearance. Of course the four engines make it easy to distinguish the A340 from the A330. However, the A340 also looks like the Ilyushin Il-86 and Il-96. The Il-96 (and Il-86) has different cockpit windows (nearly triangular last window) and taller winglets, apart from smaller differences. The Il-86 also as different engine nacelles and lacks winglets.

To differentiate between the different A340 subtypes you have to look at

• the length of the fuselage
• the shape of the engine nacelles
• the number and location of cabin doors and emergency exits
• the number of wheels on the centre main gear

The first generation A340 consists of the -200 and -300 series. The A340-200 is the shortest of the two. To distinguish it from the 4 m longer A340-300 look at the location of the second main door: at the -200 it is nearly above the starting point of the wing root. At the A340-300 it is clearly before the wing root.

The A340-300 is the longest of the first generation A340 To distinguish it from the 4 m shorter A340-200 look at the location of the second main door. This is before the wing root at the -300 and above the leading edge of the wing root at the -200.

The second generation A340 has two main recognition points compared to the series 200 and 300. They have different engines with separated fan exhausts. The middle main landing gear leg has four wheels instead of two. It is rotated forward, while the other two bogeys are tilted backward. The A340-500 is the shortest of the second series, about four metres longer than the A340-300.

The longest version of the A340, and the second-longest jet airliner in the world after the Boeing 747-8, is the A340-600. It has the same differences compared to the A340-200/300 as the A340-500, but has a clearly longer fuselage. Still the number of main doors is the same, four on each side.