China will invest US$17.4 billion over the next five years to improve its airports and build new ones, the Wall Street Journal reported. On an annual basis, the planned outlay is more than three times the average yearly investment in airports between 1990 and 2005, when a total of US$14.9 billion was spent. Gao Hongfeng, vice minister of the Civil Aviation Administration of China, told an aviation-industry gathering in Hong Kong Tuesday that the government will continue to enlarge China's three biggest airports – Beijing, Shanghai and Guangzhou – and boost the number of mainland airports from 142 to 186 by 2010. Airports in Shenzhen, Chengdu, Haikou and Xi'an are also earmarked for expansion. In 2005, Chinese airlines carried 138 million passengers, up 15.5% from the previous year, and 3.07 million metric tons of cargo, up 13.8%. The CAAC expects passenger and cargo traffic to grow 14% a year through 2010, falling to 11% annual growth from 2011 to 2020.