Query: What is the smallest airport in the London area?
Context: Stansted Airport, north east of London in Essex, is a local UK hub and Luton Airport to the north of London in Bedfordshire, caters mostly for cheap short-haul flights. London City Airport, the smallest and most central airport, in Newham, East London, is focused on business travellers, with a mixture of full service short-haul scheduled flights and considerable business jet traffic. London Southend Airport, east of London in Essex, is a smaller, regional airport that mainly caters for cheap short-haul flights.