Giovanni Bisignani, chief executive of the International Air Transport Association, said air traffic control over the congested region is a "mess" that needs to be fixed. He said flight delays are still at unacceptable levels despite some improvements.
The region's steadily growing air traffic has resulted in very crowded airspace, and planes often have to take detours or adjust their altitudes to avoid collisions, resulting in delays.
In 2009, about 2,000 flights departing Hong Kong were delayed. The figure was roughly the same in 2007 and 2008. The problem is more acute for flights heading to mainland China, with more than 1,600 delayed from January to June last year.
The situation is compounded because the military controls China's airspace, Bisignani said.
"Airspace is a finite resource from which we are working together to squeeze even more efficiency. The key will be in releasing more military airspace for civilian use," he said.
The delta's air traffic congestion has been a long-running problem that airlines and regional officials have been working to resolve.
"It's a complex problem," said Bisignani. "We have five airports in a small and congested area."
Air travel in the region has skyrocketed because of China's rapidly expanding economy, especially in southern Guangdong province, where there are tens of thousands of factories churning out electronics and other products. Many are shipped by air for speedy delivery to overseas markets.
Four airports - in Hong Kong, Macau and in the mainland Chinese cities of Zhuhai and Shenzhen - are within 65 kilometers (40 miles) of each other. Another, in Guangzhou, is 135 kilometers (84 miles) north of Hong Kong.
Hong Kong's airport use surged to a record in 2010, with 50.9 million passengers and 4.5 million U.S. tons (41 million metric tons) of cargo handled. Data for the mainland airports from 2010 was not immediately available.
Bisignani said that new routes in 2009 for flights arriving to Hong Kong from mainland China, Europe and Southeast Asia shaved about 130 miles (210 kilometers) off each flight while 10 other conditional routes in China also helped. But he said that the region's air traffic problems are still one of the top three globally, ranking alongside European airspace integration and bringing in next-generation air traffic control in the U.S.
Bisignani urged Hong Kong authorities to move ahead with plans to build a third runway at the city's airport, which could help alleviate the problems.
China's international air cargo is forecast to nearly double by 2014 to 4.2 million U.S. tons (3.8 million metric tons) from 2.1 million metric tons in 2009, IATA said.
Passenger air travel on the mainland is also surging, with the number of domestic travelers forecast to nearly double from 198 million in 2009 to 379 million in 2014. International travelers are forecast to jump to 82.1 million from about 50 million in the same period.