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 International Airport 3 Elementary Flying Training School(EFTS) and No. 4 Air Observer School(AOS), both part of the British Commonwealth Air Training Plan. The airport remained under civilian management and was used for civil and military aviation during the war years. The licence for London City Airport was issued on 6 May 1941. Improvements made during this time include: British Commonwealth Air Training Plan operations ended on 31 December 1944 with the closure of No. 4 Air Observer School. After the war the airport remained under the control of the Department of Transport. In approximately 1942 the aerodrome was listed at with a