Passengers prepare to pass a security check at Beijing Capital International Airport. Provided to China Daily

With Spring Festival travel crowds converging on the capital's airport and crime likely to soar as a result, police protecting the hub say they will fight to ensure illegal activity is grounded, both at the terminal and in the air.

Officers said the battle to contain crime will be made easier this year because of unprecedented cooperation between officers on the ground and those in the air.

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The Air-ground Cooperation Mechanism allows the airport's police to work closely with undercover agents on planes and has already played an important role in tackling in-flight thefts, said officials at the Beijing Capital International Airport Branch of the Beijing Municipal Public Security Bureau on Tuesday.

The branch investigated a total of 14 thefts and took 13 suspects into custody thanks to the system, saving losses of more than 550,000 yuan, according to Hu Jianhui, director of the airport police.

The cooperation mechanism allows airport police to share case information with airlines, which helps the airlines to take precautions against thieves in the air. The crime detection rate at Air China increased by 60 percent year-on-year as a result while the incidence of criminal incidents at Hainan Airlines fell by 70 percent year-on-year.

Cases of in-flight theft are not rare. A passenger recently reported the loss of 9,500 yuan while on a flight from Zhuhai to Beijing.

Ground police officers identified three suspects, who were set to leave Beijing the next day. Officers reported the trio's activities to agents on the aircraft the next day and the men were caught red-handed trying to steal more money.

"The cooperation mechanism also helps police establish a database and bring the illegal activities on planes under control," said Gao Jianhua, vice-director of the airport police.

The crime crackdown on the ground will also include new efforts in boarding areas and at security checkpoints.

Officers said thieves have several tricks up their sleeves.

The most common trick is fake booking websites for flight tickets that try to cheat passengers out of their ticket money, said Pan Jianqiang, head of the police station at Terminal 3.

Other tricks include fake telephone booking companies with numbers that are similar to the real airlines.

"Many illegal agents book seats on the real airlines' homepages and immediately release the hold after receiving the passengers' payment," said Guan Yin, a chief of the T2 police station.

"Many passengers only find their tickets were cancelled or that they are holding fake tickets when they arrive."

Police stations at the airport have received five reports of ticket fraud since December.

Officers suggest that passengers only book tickets through airlines' websites and that they do not transmit payment into a personal bank account.

Passengers should capture the screenshot of the moment they made payment in case of disputes and call the airlines to check up on the tickets.

Beijing Capital International Airport is ranked as the world's second-largest airport and had almost 74 million passengers in 2010, a year-on-year increase of 13 percent on 2009.

The number of passengers is likely to hit 80 million this year. A total of 8.3 million passengers are expected to travel through the capital's airport during the Spring Festival migration between Jan 19 and Feb 27.

Tan Zongyang contributed to the story.