About 13,600 new aircraft, worth about US$1.2 trillion, will enter service with the world's airlines over the next 20 years, Airbus Industrie has forecast. An Airbus report, which takes into account Asia's economic downturn, says the world's air fleet will grow by 8,200 aircraft to 17,920 aeroplanes by 2017. Another 8,500 aircraft will be required to replace older or noisy planes that cannot meet new regulations and have to be scrapped. But these 'new' aircraft include 3,100 second-hand jets that will be sold by large airlines to smaller operators. Consequently, the actual number of new aircraft will total 5,400. Airbus has not produced individual figures for cargo aircraft, but rival Boeing says 650 new freighters, mostly conversions from passenger aircraft, will be needed between now and 2017. Airbus says the biggest growth will be in the mainland where the number of aircraft is set to rise by an average 7.8 per cent a year, from 425 planes at the end of 1997 to 1,518 by the end of 2017. In the Asia-Pacific region, aircraft numbers will grow by an average 5.1 per cent over the next 20 years. Overall, the mainland and the Asia-Pacific region will have 25 per cent of the world's air fleet by 2017, compared with 19 per cent now.