BEIJING - Many travelers in China can remember a time when they managed to get aboard a plane for their scheduled departure only to have to wait for hours before leaving because of troubles with "air traffic control".

If the Civil Aviation Administration has its way, such delays will be a thing of the past.

In response to complaints about late departures, the civil aviation authority announced over the weekend new policies aimed at getting planes to be more punctual.

Xia Xinghua, deputy head of the Civil Aviation Administration, told Xinhua that air traffic controllers are now required to ensure that planes take off within half an hour of when their cabin doors are closed.

Those workers are also to approve the departures of flights that have already been delayed for more than two hours, he said.

In the past, traffic controllers have tended to postpone the departures of flights that are already late so that other flights can be kept on time.

The new policies will have one important exception: They will not be in effect when the weather is bad.

When a large number of delays are brought on by bad weather or other complications, traffic controllers will work with the military, which controls airspace, to temporarily open up routes along which stranded planes can fly, he said.

Airline companies are also being encouraged to communicate more with air traffic controller and to arrange proper times for passengers to get on board.

Many critics contend airlines often move passengers onto an airplane to avoid paying the compensation they would owe if a delay occurred while the passengers were still in the airport.

While trying to ensure more flights leave on time, officials have not lowered the priority they place on passenger safety, said Li Jiaxiang, chief of the Civil Aviation Administration.

The policies are in part a result of the frequent flight delays that have been caused by thunderstorms this summer, raising the ire of many passengers.

Wan Changming, spokesman for the public security bureau at the Beijing Capital International Airport, said police officers have received 253 calls in June and July from people who want them to deal with disputes stemming from flight delays. That number is up 166 percent from what it was this past year.

Most of the disputes have concerned angry passengers who beat up airline workers, broke into airport parking aprons or refused to leave a plane.

Altogether, scheduled flights in China have become less punctual in recent times, despite the measures that have been taken to prevent that from happening. In 2010, the percentage of flights that left on time dropped below 80 percent for the first time, falling to 75 percent, according to the Civil Aviation Administration.

Airline sources who requested anonymity said it will be impossible to meet the goals of the new policies, largely because the traffic at big airports is heavy and departure times are hard to predict.

Many netizens also doubted the measures will actually help to prevent flight delays and speculated that the airlines will find a way around the authority's requirements.

Jing Lei, a university student, said the new policies could make it take longer to check in luggage and board planes.

"Passengers will be kept waiting as usual, except that they now will wait outside the plane instead of inside," she said.

Zou Jianjun, an associate professor with the Civil Aviation Management Institute of China, said he believes the new measures might lead to more disputes at airports.

"Taking off 30 minutes after the cabin doors are closed is a requirement in normal conditions," he said, urging passengers to be more rational. "But many passengers could misunderstand that and use it as an excuse to seek compensation when bad weather causes delays."