The Airbus a350:
Airbus originally intended to develop an aircraft called the a330-200Lite, a minimum change aircraft that made use of better engines and composite materials, specifically to counter the Boeing 777. This rather halfhearted proposal received lukewarm reception.
No details of the improved a330 were published until the 10th of December, 2004. This was when EADS and BAE systems have Airbus authorisation to offer a further developed project called the a350. It was specifically intended to counter the new boeing 7E7 (later restyled as 787 dreamliner) and was to be powered by either the rolls Royce Trent 1000 or the GEnx.
At the Paris airshow in 2005 Airbus revealed the a350 stats and 787 comparison. It announced two versions, the a350-800, to carry 253 passengers up to 8800nm, and the a350-900 to carry 300 passengers 7500nm. Both versions had a MTOW of 540000lbs, and both were to be powered by GEnx engines (although due to issues with general electric they were switched to the Trent 1000).
Besides the new engines, this was still an a330, which could have stayed as the a350 we see today. After the aircraft was subject to scathing criticism, Airbus listened to the market, creating the a350XWB.
Airbus offered a third version, the a350-1000 stretched to make room for 412 passengers. By late 2007 Airbus had further added proposals for the ultra long range a350-900R, the a350-900F freighter and the luxurious a350-XWB Prestige.
Due to issues with general electric being unwilling to offer an engine to match the a350, Airbus switched to rolls Royce who offered them a specifically tailored Trent 100, to be renamed TrentXWB offering thrust levels from 75000lb to 95000lb.
Airbus calculated that the airframe would be 55% metal and 45% composites, which was later changes to 52% composites, consisting of Al-Li Ti and steel. The wing had an aspect ratio of 11.5, the highest on a commercial airliner, a multifunctional flap and spoiler system which lead on from the variable camber tests on the a340.
The original cockpit design features 4 windows howecer this was changed to the 6 we see today. The multifunction displays and instruments are the most advanced found in a civil airline today, with the a350 being therefore one of, if not the most, advanced airliners today.