China Eastern Airlines (CEA) is facing a 1.5 million yuan (about 214,286 U.S. dollars) fine for early flight returns in southwestern Yunnan Province, Xinhua learnt from the Civil Aviation Administration of China (CAAC) on Thursday.
CAAC attributed the incident largely to some pilots of CEA's Yunnan branch, saying they had ignored the passengers' interests and disrupted the flights on purpose.
According to a CAAC investigation, three of the 21 flights were forced to return because of poor weather or aircraft failure.
However, an investigation was still underway as the reason for the other nine early flight returns hadn't been identified because of problems with the quick access recorder (QAR) data.
As punishment, CEA, one of the country's three major carriers, would be stripped of some routes and flights operated in Yunnan Province, but the detailed arrangements had yet to come out.
CAAC urged the CEA to ensure flight safety and severely punish those responsible for the incident.
From March 31 to April 1, 21 flights returned to their departure points in Yunnan Province, leaving more than 1,000 passengers stranded at Kunming Airport, the Yunnan capital.
CEA originally said the incidents were due to bad weather. However, flights with other airlines flying the same routes landed on schedule during the same period.
The company finally admitted some pilots on the 21 flights deliberately turned their aircraft around and promised to offer compensation of up to 400 yuan to passengers affected.
Earlier reports said the pilots took the extreme step to express their grief with the company over poor working conditions and low wages.