As the Airport Authority's campaign for a third runway at Hong Kong International Airport moves into high gear, it feels increasingly like the cart is being put before the horse. Promotional videos and materials are being churned out and the government's three-month consultation is under way, with its focus on increasing capacity. Of course, the tens of billions of dollars involved dictate that every possible aspect has to be publicly examined and that there is a thorough debate. However, it ignores the fundamental point that increased capacity, allowing for vastly more aircraft to fly in and out, will not be fully utilised unless there is hard-and-fast agreement on flight paths with Shenzhen and Macau.

It is all a matter of airspace. As the authority pointed out in its technical report, fully realising the potential capacity gain of another runway requires redesigning flight paths over the Pearl River Delta region. Hong Kong would need 'a northern circuit, long final approach tracks and independent arrival procedures'. As yet, despite three years of bargaining, no deal to allow these has been signed.

Civil Aviation Department officials are nonetheless positive. They say that consensus was recently reached, although they admit that nothing formal has yet been agreed. With all airports in the region competing for rapidly expanding business and jealous of what they have and eager for more, a signed-and-sealed deal is essential. Without it there can be no certainties or guarantees.