China Southern Airlines Co, the largest airline by fleet size in Asia, announced on Thursday it would withdraw from SkyTeam when its agreement with the airline alliance expires on Jan 1.

"Based on the needs of the company's development strategy and to better align with the new trend of cooperation model in the global aviation industry, the company decided not to renew its SkyTeam membership agreement from Jan 1 and will complete the transition arrangements in 2019," it said in a statement.

China Southern said it would "explore the possibilities to establish new partnerships with advanced airlines, promote bilateral and multilateral cooperation and provide quality services to passengers around the world."

The carrier pledged to work closely with SkyTeam on a cooperative process during the transition period to ensure a sound transition for customers and partners.

China Southern Airlines signed an agreement last year to sell a minority stake to American Airlines Group Inc, which belongs to another airline alliance Oneworld.

Cross-alliance investment and cooperation have been on the rise in the past few years.

Airline alliances have become more loosely-knitted, said Qi Qi, an aviation industry analyst, cited in a report by The Beijing News.

Amid intensifying competition in the industry, the competitive situation among alliances has changed and airline companies have been seeking cross-alliance cooperation based on their own development, Qi said.

Airliners are freer to cooperate with different counterparts without the binding of an alliance, said Lin Zhijie, another analyst.