As London’s main international airport at Heathrow nears full capacity, momentum is growing in the U.K. for a major new hub in the Thames Estuary. London Mayor Boris Johnson has been lobbying hard for an estuary airport for two years. Recently, architectural heavyweight Sir Norman Foster proposed a rival $80-billion estuary project that includes high-speed rail, tidal power and a major new utilities and data spine.

Under Norman Foster's plan, more than a third of the 40,000-hectare airport would be on reclaimed land.