Originally Posted by SEA_Tigger
You cannot physically fit nine-abreast seating in an A350 (well you can, but at like 15" or less width).
While the cabin interior is wider then the A330/A340, the fuselage diameter is not, so 2+4+2 is as many as you can put in. Right now that seating is 18" wide, so it is possible Airbus could offer 19" wide seats.
Air Transat of Canada does put 3-3-3 seating on their A310 and A330s.