Singapore Airlines Ltd., the world's second-largest carrier by market value, said it may order Airbus SAS's A350-1000 jet as the European planemaker plans improvements in range and payload.

The airline is also awaiting details of enhancements to Boeing Co.'s competing 777-300ER before deciding which model to purchase, Chief Executive Officer Goh Choon Phong said yesterday at a briefing at Airbus's headquarters in Toulouse, France. He declined to discuss how many planes the carrier may buy.

Airbus in June said it would delay the introduction of the A350-1000 so it could make changes including the use of improved Rolls-Royce Holding Plc Trent XWB engines. Singapore Air has 20 of the smaller -900 variants on order, and it also signed a deal for eight 777-300ERs in August because of Asia's growing regional and long-haul travel.

Goh also said that the carrier was concerned about a potential economic slowdown and the possibility of tighter credit following Moody's Investors Service Inc. downgrade of Credit Agricole SA and Societe Generale SA, France's second- and third-largest banks.

"The most strategic concern is how the economy is going to go," he said. "The recent downgrade of banks in France is a concern -- the impact, if any, on the liquidity of banks, and whether there's a contagious effect on the rest of the economy."

A380 Handover

Goh was in Toulouse as Singapore Air took delivery of its 13th double-decker A380. The carrier will get another next month and it expects to have received all 19 of the planes it has ordered by mid-2014.

The airline is reducing the number of seats on the last eight A380s in the fleet to carry more business-class passengers. The first 11 planes had 471 seats, while the final eight will have 409. That includes an all-business class top floor fitted with 86 seats. The carrier also has options for six more A380s.

Airbus is due to begin deliveries of the A350-900, the most popular of the A350's three versions, around the end of 2013. Singapore Airlines will be the second carrier to receive an A350 after Qatar Airways Ltd., Goh said.

Changes to the A350-1000 variant include work on the landing gear and the outer part of the wing, Airbus said. The improved performance will allow the aircraft to service routes such as Shanghai to Boston. The planemaker has also delayed the smallest version of the A350 to focus on developing the -900 variant and revamping its single-aisle A320.

Boeing's plans to upgrade the 777 include the adaptation of technology used on the new 787 Dreamliner, Marc Birtel, a spokesman, said by e-mail. He didn't elaborate and said Boeing doesn't comment on discussions with customers.