CHINA continues to be the news of the moment in airline terms with the announcement from Beijing and Washington that air service between the USA and mainland China will grow nearly fivefold by 2010. Under a new treaty agreement the number of weekly commercial flights (including cargo) by the two nations airlines will rise gradually to nearly 500. Currently, United and Northwest airlines are the only US carriers allowed to serve mainland China but American has already announced its intentions and both Continental and Delta are known to be studying plans for China service. The new treaty will allow airlines from both nations to serve any city in the other country, US passenger airlines presently limited to the major five Chinese cities.