TOULOUSE, France—Airbus landed the first firm contract for an updated version of its best-selling A320 aircraft from low-cost carrier Virgin America, helping push the European plane maker's 2010 orders past those of U.S. rival Boeing Co.

The contract, signed Dec. 29, is for 30 of the New Engine Option version of the A320, which Airbus is touting for its greater fuel efficiency and reduced emissions, and 30 of the current version of the popular single-aisle jetliner.

The...