What is the relationship between Xiamen Airlines and China Southern Airlines in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

Chinese carriers, boosted by drops in fuel costs, were the region’s most successful, with China Eastern Airlines, Hainan Airlines, Cathay Pacific Airways, China Southern Airlines and Xiamen Airlines all making it in the top 25 rankings.

Answer: parent_organization