London is served by six airports. All intercontinental flights land at Heathrow or Gatwick. Low-cost carriers fly to and from Gatwick, Stansted, Luton and Southend. Domestic and European flights also depart and arrive from London City Airport. Heathrow is the main airport and is reachable by Underground (about 45’ from Central London and the cheapest option at about £5.10) or by train, which arrives at Paddington Station in 15 or 30 minutes depending whether you use the Heathrow Express (more expensive at around £20 one way) or Heathrow Connect (about £10 one way).
From Gatwick airport, about 45 km south there are non-stop trains to Victoria station or stopping services (much cheaper and only slightly slower) to Victoria or London Bridge. From Stansted, about 56 km north-east there is an express rail service to Liverpool Street (about £20 one way / 50’ journey). Finally Luton is 51km north of the capital and served by regular trains from / to Kings Cross and Southend is a minor airport used by Easyjet, 56km east of London served by trains to and from Liverpool Street station (1hr). There are also buses arriving at either Victoria (Heathrow, Gatwick, Luton) or Liverpool Street (Stansted / Southend), but they tend to get stuck in London’s chaotic traffic.
By far the most convenient airport is London City. Built in the former docklands, it is pitched to the business customer, generally time-poor. Here the check-in is ultra-quick and gates are reached in 5 minutes walk. Travel to and from is also very easy - the DLR (Docklands Light Railway) connects the terminal to Bank, heart of the City in 20-25’ and for less than £4.
Eurostar trains from Brussels and Paris arrive at St Pancras Station, which is by far the most convenient mean of transport from these two European cities.