Trade and exchange shape all aspects of human life, most significantly our cities. In the 21st century, the century of air-trade, the most successful cities will grow up around airports rather than vice-versa. The statistics speak for themselves: air travel is growing by 5% annually; in 2007 30% of all world trade was moved by air; 7 times more high value jobs occur in aerotropolis conurbations than they do in "down town" equivalents; and China is building 100 airports for 2020.

Some cities will boom, while other more traditionally designed cities with no room for airport expansion will dwindle. With Heathrow at a full capacity, Choa highlights the dangers for sustaining London's aerotroplis status.