A plane of China Southern Airlines is pictured at the Zhijiang Airport in Huaihua city, Central China's Hunan province, July 17, 2013. [Photo/IC]

GUANGZHOU - China Southern Airlines on Friday said it plans to increase its fleet size by about 43 percent to 1,000 aircraft by 2020.

The country's largest air carrier by fleet size said it is expected to carry 160 million passengers annually in 2020.

China Southern leased a new Airbus A321 on Friday, bringing its total number of aircraft to 700.

This made it the world's fourth largest airline by fleet size after American Airlines, Delta Air Lines and United Airlines, according to the International Air Transport Association.

The expansion in its fleet size is mainly due to the opening of more international routes, the airline said. Currently, its international flights carry 31 percent of its total passengers.