He said the airport is currently "researching what resources, both in the air and on the ground, can be used".

He said the capital airport was designed with a fourth runway, which can increase passenger capacity by at least 10 to 15 percent. But due to the limited airspace available to civil aviation, building the fourth runway has not been on the airport's agenda.

Ouyang Jie, a professor at the Civil Aviation University of China who specializes in airport studies, said the three runways at the capital airport have almost reached their maximum capacity due to the limited airspace.

"Adding a fourth won't help with the traffic pressure, because without enough airspace, planes won't be able to take off or land on the additional runway," he said.

"The airport's infrastructure will have no problem handling 90 million or more passengers a year in the coming years, but the airport will have to sacrifice its service quality," he said.

He suggested the capital airport divert some of its domestic passenger traffic to neighboring airports, such as Tianjin or Shijiazhuang.

It's a feasible option because the airports in the two cities are connected to Beijing by high-speed trains with only an hour's travel time, he said.

But industry insiders said the market may not accept the arrangement, and most passengers may not opt for flights to Tianjin or Shijiazhuang instead of Beijing.

Zhang, the airport's general manager, said the airport is planning to use an idle section in the third terminal building that was originally reserved for handling international travelers.

The section will be used next year to handle the overflow in domestic air traffic.

Contact the writer at xindingding@chinadaily.com.cn