CHINA Eastern Airlines has suspended or demoted 13 pilots involved in its "flight-return" debacle in southwestern China's Yunnan Province.

The Shanghai-based airline canceled a captain's flying license and expelled him from the Communist Party of China, according to a statement on the carrier's Website.

It suspended three flight instructors and five pilots from work. Two instructors and two pilots were demoted to first officers and received warnings from the Party.

Eight officials of the carrier's Yunnan branch also received warnings from the Party and six were sacked, including the branch's General Manager Yang Xu and Party Secretary Li Mingdao.

Twenty-one flights returned to their departure point just after taking off from Yunnan on March 31 and April 1, severely impacting on the travel plans of more than 1,000 passengers.

An investigation showed that 11 flights were disrupted by pilots intentionally.

The Civil Aviation Administration has stopped the carrier's Kunming-Xishuangbanna and Kunming-Dali flights as punishment.

It also reduced the number of China Eastern's flights from Kunming to destinations such as Lijiang, Zhongdian, Mangshi, Lincang, Simao and Wenshan.

Conflicts between pilots and state-owned airlines have intensified in recent years.

The country has 12,000 civilian pilots, but official figures predict that the total number of flights will increase 80 percent by 2010 and 6,500 more pilots will be required.