Flights in and out of the international airport for Shanghai, China’s business capital, were suspended for at least several hours Friday, with airline staff saying military exercises were thought to be responsible.

The disruptions began around 2 p.m. (0600 GMT) local time, with flights to Pudong International Airport delayed, canceled or diverted to other airports in the region. About four hours later, flights were beginning to board.

The city government said flights were suspended “to control air traffic volume.” City officials would give no further explanation and neither would airport staff.

A man who answered Pudong airport’s flight information hotline said that the restrictions had been lifted by late Friday and that flights Saturday would not be affected.

Ground staff for Japan Airlines Corp. and All Nippon Airways Co. said the disruptions were due to military games.

“It’s air force exercises,” said a staffer at the counter for Japan Airlines at Pudong. She would not give her name.

A passenger aircraft and a cargo plane, both operated by Japan Airlines Corp., were forced to turn back to Tokyo on Friday after Chinese aviation officials denied them landing permission in Shanghai due to airspace restrictions, said airline spokesman Yasuo Ikeda.

Chinese air controllers notified JAL’s Shanghai office at around 3 p.m. (0600 GMT) that they were restricting traffic at airports in southern China, including Shanghai, for about half an hour and that the two flights, which were scheduled to land in that time slot, had to turn around and go back, Ikeda said.

“We suspect it was because of Chinese military exercises, though they are not officially saying that,” Ikeda said. “At least it’s not because of the weather.”

He said China told the airline that there might be a possibility for airspace restrictions between Friday and Sunday, but provided no specifics.

The restriction also caused delays for two other Shanghai-bound JAL flights that left Narita and Fukuoka in southern Japan later Friday, though they were eventually allowed to land, Ikeda said.

Phoenix Satellite Television, a Chinese-language broadcaster in Hong Kong with close ties to the Beijing government, reported that military exercises were being conducted in Hangzhou Bay, south of Shanghai.

The rumors of military exercises could not be officially confirmed; the military rarely comments on its activities. Phone calls to China’s Civil Aviation Administration rang unanswered late Friday.

But the military has broad authority over China’s air space, and flights along the southeastern coast are occasionally diverted, delayed or canceled due to military movements in the region, which faces Taiwan.

Such activities have rarely caused the outright closure of a major airport like Pudong, which serves China’s biggest city.

Some flights were rerouted to Shanghai’s Hongqiao Airport, to the west of the city. Flights there also were disrupted by the air restrictions. Other flights were diverted to Nanjing, a city two hours away from Shanghai by train.

Although weather in the area was somewhat hazy Friday, it was not unusually so.

In decades past, commercial flights were often canceled or postponed, sometimes for days. Civil aviation authorities have given several reasons for closing airports, from thunderstorms to military exercises.

“Many travelers think ‘the sky is so vast. How could it be congested on the ground? Just take off,”‘ state media quoted Zhang Yuehua, a vice director for the Civil Aviation Administration’s traffic control center, as saying after Beijing canceled hundreds of flights this summer to ease congestion. “In reality, it’s just not like that.”

Source: AP