Economy of London project is construction of 42 km (26 mi) of new tunnels connecting stations in central London including a branch to Canary Wharf in east London. It is Europe's biggest construction project with a £15 billion projected cost. An additional line, Crossrail 2, has been proposed. London is served by six international airports which are the world's busiest city airport system by passenger traffic. These are Heathrow, Gatwick, Stansted, Luton, London City, and Southend. There are a number of proposals for expanding airport capacity for London including expansion of London Heathrow Airport and expansion of Gatwick Airport. The principal argument in
London Stansted Airport traveller market, both are run from the short stay car park Stansted has been designated by the UK Government as its preferred airport for any hijacked planes requesting to land in the UK. This is because its design allows a hijacked airliner to be isolated well away from any terminal buildings or runways, allowing the airport to continue to operate while negotiations are carried out, or even while an assault or rescue mission is undertaken. For this reason Stansted has been involved in more hijack incidents than might be expected for an airport of its size. London Stansted Airport London