In response to the Boeing 787 Airbus launched the A350. Initially this was an A330 with new engines and improved aerodynamics. However, Airbus quickly found out that a slightly improved A330 could not compete with the all-new, composite fuselage Dreamliner. Thus the original A350 became the A350XWB, extra widy body. Like the Boeing 787 it features a composite fuselage mated to metal wings.
Not surprisingly the A350 looks a lot like the Airbus A330, especially the second generation A330-800/900, and the Boeing 787. One look at the cockpit windows is enough to keep them apart, however.
The difference between the different A350 subtypes is only the length of the fuselage.
Airbus A350-900 & -900ULR
The A350-900 is the shortest of the two main variants. While counting windows between main cabin doors is an option to recognise it, you'd better look at the main landing gear if possible. It has four wheels per leg instead of six on the A350-1000.
The version is also available with additional fuselage fuel tanks to increase the range. This subtype is known as A350-900ULR. From the outside there is no difference with the normal -900.
Seven metres longer than the A350-900 is the A350-1000. To accommodate the higher weight the -1000 has six wheels on each main landing gear leg compared to four on the A350-900.
Confusion possible with
The A330 and A350 are externally quite similar. However, the cockpit windows (actually the whole nose) of both aircraft are different. Moreover, the dorsal fin of the A330 is larger and the winglets of the older A330-200 and -300 and not curved.
At first the Boeing 787 and Airbus A350 may have a large resemblance. However, look at the cockpit windows (four on the 787, six on the A350), top of vertical stabiliser, tailcone and wingtips and you will notice the differences.