Growth in Asia-Pacific economies will boost demand for freight aircraft well into the 21st century, executives from Boeing and Airbus said at a transport conference. James Edgar, Boeing's regional director for cargo marketing forecast that freight earnings - measured in revenue tonne kilometres (RTKs) - will grow by an average 6.6 per cent a year between now and 2014. "This means that the market will roughly triple over the next 20 years. Not surprisingly, Asian freight markets will lead world growth," he said. This included internal Asian routes as well as links with Europe and North America.