China Southern Airlines is to quit membership of the SkyTeam global airline alliance.
American Airlines, a leading member of rival airline group Oneworld, last year spent $200 million buying a stake in China Southern.
Among the other members of SkyTeam are Delta Air Lines and Air France KLM.
China Southern’s decision “reflects its strategic development, the changing trends of the global aviation industry and the evolution of alliances”.
The move to not to renew its contract with SkyTeam comes into effect from January 1.
SkyTeam and China Southern said they have agreed to work closely together to ensure a seamless transition for all customers and partners.
The process will run throughout 2019 and will complete by the end of the year.
SkyTeam CEO Kristin Colvile said: “Network has always been the foundation of SkyTeam.
:Our new value proposition retains that strong integrated network and combines it with our continued focus on improving customer experience through technology.
“China Southern has been a valued member of SkyTeam. We respect its decision and wish it well.”