Beijing Capital International Airport (BCIA) has become the latest mainland aviation play to capture investor interest in a booming air travel market. The airport has languished below its listing price since March. But it rose 25 per cent to close at an historic high of HK$2.10 yesterday, adding to a 10 per cent gain on Friday. The surge follows similar leaps in the share prices of China Southern Airlines, China Eastern Airlines and the China National Aviation Co (CNAC), which owns 43 per cent of Dragonair. The three Hong Kong-listed airlines broke through to record closings last week amid expectations the mainland's air-transport market would outpace original forecasts for the year. Asia's economic recovery, the expected drop in fuel prices, higher air fares combined with flagging sentiment for technology stocks returned investor interest to the region's aviation sector. A 34 per cent earnings upgrade for BCIA's 2000 results by UBS Warburg spurred the run for BCIA's H shares, which are among the most undervalued stocks traded in Hong Kong. The mainland air-travel market is expected to grow faster than any other country's over the next two decades, with Boeing predicting nearly 10 per cent annualised growth for the years to 2020. However, Boeing has indicated that these forecasts may be understatements as they were not adjusted to take into account the potential impact of the mainland's World Trade Organisation membership bid. The aircraft manufacturer's views were supported by a number of aviation analysts, who saw the increased trade, economic growth and business ties from WTO membership further stimulating demand for air travel and air freight. WTO membership aside, China Southern's latest traffic figures offered the first evidence that previous estimates might have been on the low side. The Guangdong-based carrier shot up more than 23 per cent last week to a peak of HK$2.40 on Wednesday after it revealed better than expected first-half traffic figures to a group of fund managers and journalists. China Southern expects traffic to show growth of 15 per cent this year, outstripping previous forecasts. The news sparked a rally, with China Eastern gaining 12.6 per cent to a high of HK$1.16 and CNAC soaring 18.8 per cent to a peak of HK$1.64 on Wednesday. Although air-service arrangements fell outside of the WTO agreement, membership to the body, among other things, is expected to accelerate the pace of deregulation. The mainland has agreed with the United States to double the number of weekly flights which can be flown by both mainland and US carriers to 54 over the next seven years. Unlike the airlines, which are exposed to increased competition as the mainland deregulates, airports such as BCIA stand only to benefit from the increase in traffic. 'Whether the additional traffic comes from Chinese or foreign carriers really doesn't matter,' an analyst with a US brokerage said.