Airbus Americas President Barry Eccleston told an audience in Seattle that the European aircraft maker was switching the plans for the plant in Mobile, Alabama, to accommodate growth in orders for the larger plane.

The first one off the line will be the A321ceo, or "current engine option" in April 2016, with "new engine option" or A321neos, to follow later, he said, according to the company.

In the year through September, Airbus has booked 311 gross orders for the A321, including 135 with the current engine option and 176 for the A321neo with newer engines.

The A321 seats about 185 passengers in a two-class configuration but can accommodate up to 220 for economy carriers.

The plane is a rival to the Boeing 737-900 and 737 MAX.

Airlines have been improving their efficiency by "upgauging" to larger jets that accommodate more people, which lowers the per-seat cost.

(Reporting by Alwyn Scott; Editing by Cynthia Osterman)