Airbus is expecting 50% of its future single-aisle production to centre on the A321, the largest model in the A320 family.
The A321 accounted for 21% of orders and 18% of deliveries across the family last year, while the proportions for the smaller A319 have been falling.
Airbus executive vice-president for strategy and marketing Kiran Rao says the A321 is "gaining in momentum".
"We see that we'll be producing at least half of our production, going forward, on the A321," he says. "Because that's what the market needs, that's what the market expects."
Airbus order and delivery data for the end of May 2013 shows that the A321's backlog of 867 aircraft is more than five times the A319's figure of 156.
The re-engined version of the aircraft, the A321neo, is due to enter service at the end of 2016.
Airbus is also developing a higher-capacity version of the type - for service entry in the second quarter of 2017 - which will raise maximum seating from the current 220 to 236.