China Eastern Airlines (CEA) is in hot water with passengers who are seeking compensation over flights that they claim were delayed, cancelled or turned back in mid-air for mysterious reasons.

Adverse weather has been cited by the airline in many cases, but some flyers think that a labor dispute by pilots may be the real explanation. No extreme weather conditions were reported in the province on March 31. In Kunming, official meteorological reports showed that it was sunny with light wind. In Lijiang, another city where flights were affected, it was partly cloudy.

On March 31, 14 flights scheduled to leave Yunnan's Kunming airport for Lijiang, Xishuangbanna and Dali -- also in Yunnan -- were cancelled. At least 1,400 passengers were stranded in Kunming and hundreds more at other airports.

Some flights took off but turned back midway, with pilots citing bad weather -- even though other airlines were flying normally. And in other cases, flights landed at their destinations but took off without allowing passengers to disembark, the Shanghai Morning Post and other media organizations have reported.

A passenger surnamed Wang, headed for Beijing, said that he planned to leave Xishuangbanna at 7:40 p.m. on March 31 on flight MU5715 but the plane did not arrive in Xishuangbanna until midnight. "I will not get back to work on time." said Wang. He said that he had already faxed CEA, which had promised to resolve the problem within three working days.

When asked about this, CEA's customer service department cited severe weather. But some passengers weren't satisfied with this explanation and plan to seek compensation.

On April 4, Yuan Yiting and Li Qin, from Hangzhou, Zhejiang Province, came to the customer service counter at Kunming airport in the morning, demanding that CEA compensate them for losses.

They said they were among 10 passengers who came to Kunming airport on March 31 to board flight MU5760 to Lijiang, but the plane did not arrive until 8 a.m. the next morning.

When they finally took off, the plane turned around in mid-flight and flew back to Kunming. "I could even see the aircraft runway in Lijiang airport and it was really sunny that day," said Yuan. "I insist on being compensated."

A source from CEA said that the carrier had faced a raft of complaints from passengers, some of whom had gotten 400 yuan (US$57) to 500 yuan in compensation.

Some passengers speculated that weather wasn't the real problem. This past week, there have been reports in the Chinese media that pilots were engaging in industrial action. Forty Shanghai Airlines pilots had called in sick on March 14 and at the newly founded Wuhan-based East Star Airline, 11 pilots asked for sick leave on March 28.

The reports said that pilots were angered by being required to sign 99-year (lifetime) contracts with state-owned airlines that call for them to pay their employers up to 2.1 million yuan in compensation if they quit. Airlines in China, which are mostly state-owned, directly pay the high costs of pilot training.

On April 4, China's aviation regulator, the Civil Aviation Administration of China, denied the reports, insisting that weather was to blame.