London Airports Guide
Gatwick Airport in West Sussex and with its North and South Terminals is second only to Heathrow in terms of passenger numbers, as Britain's number 2 airport. Gatwick provides connecting with airports worldwide, far too many to mention in here. From London the airport is connected via train and coach and is located just south of London.
London's busiest airport and also one of the busiest in the world, with 5 Terminals and serving many national airlines, Heathrow Airport is many people's main entry point into the UK and tends to be very popular with business travelers.
Stansted airport is not as large as Heathrow and Gatwick but it is nevertheless a major entry and exit point into England. The airport tends to be favoured by the budget airlines such as Ryanair. You can often get lower cost flights but the airport is more inconvenient in terms of access from central London.
Luton London Airport
Although not really actually in London, but renamed to Luton London Airport for marketing reasons, this is a good airline for budget flights. Easyjet are one of the main airlines serving Luton, Luton is not as close as Gatwick or Heathrow to the centre of London.
London City Airport is the closest for the Olympic stadium and area and is a great business flights arrival and departure airport, given its closeness to Canary Wharf and the Docklands. A great option if you are flying into the city to attend an exhibition or conference at the ExCel Exhibition Centre.
Getting to the airports
One of the key questions I know you will have is how to get to and from the various airports in London and if it is possible to get between let's say, Heathrow and Gatwick. If you are interested in airports and how airports organise their wayfinding you might also be interested about wayfinding in airports. For transport on the other hand, see below:
All of the airports have vast car parking areas and each airport tends to have a variety of services such as long stay, short stay and drop off (where you drop the car and keys off right outside to the terminal).
Another option is to use car rental and to drop the car back with the rental agency and thus to in effect to not need to park and to still in effect, have your transportation to the airport.
Train and Rail
The services vary according to which airport you are trying to get to. Heathrow is easy to get to from Central London given that the underground (subway trains) network includes a line which takes you to the airport. For Gatwick Airport, you can use the Gatwick Express or you can use the normal rail service and which s roughly half the price but with fewer trains available i.e. a less frequent service.
National Express offer services to all the main London served airports and from most major cities in the UK. From central London just head to Victoria train station and you can connect to all the airports via National express and also by a few other smaller providers.