But like the Dreamliner, the A350 reduces fuel burn through lightweight construction using carbon fibre and more efficient Rolls Royce engines.
Its fuselage is stronger than older planes and can have bigger holes cut into it and therefore has bigger windows. This strength allows a higher cabin pressure with more oxygen to lower the cabin cruising altitude from 8000ft on current aircraft types to 6000 ft - this reduces passenger fatigue.
Cabin air is also recycled every three minutes and the plane is equipped with wifi that costs about $25 for the Hong Kong-Auckland flight.
The plane's wing adapts its shape in flight to maximise aerodynamic efficiency, give it greater lift and less drag. It has a higher cruise speed and Airbus says its perceived levels of external noise are 50 per cent less than older planes.
The A350 is estimated to have cost the European aerospace conglomerate close to $17 billion to develop over eight years.
While the programme had some problems, Airbus learned from Boeing's trouble. When the Dreamliner started having problems with its lithium-ion batteries Airbus reverted to more traditional powercell units.
In 2014 the Airbus brought an A350XWB to Auckland on a test flight.
WATCH: Inside the new Airbus A350XWB:
Cathay has configured the first of its A350s with 38 Business Class seats, 28 Premium Economy and 214 Economy. The seats are the key selling points for passengers.
Business Class seats
Single touch control to get the seat from upright to fully flat and the bed is slightly longer than those on the A340, and configured four across.
Additional stowage including a dedicated spot for a water bottles. There's an 18.5 inch TV with a 4.3 inch video handset - among other functions, passengers can let crew know when to not to disturb or wake them up.
Premium Economy
Full-length leg rest on all seats, pitch is increased to 40 inches, dimmable personal reading light, more stowage, including a tablet holder. Also has nifty slide-out cocktail table. A 2-4-2 layout in a separate cabin.
Economy
A 3-3-3 configuration. Slimline seats have a four-way adjustable headrest and a tablet holder. Power outlets at the bottom front of every seat and your own USB port. The vertical side walls mean more space around window seats.