The biggest of the four is London Heathrow Airport (LHR), the world's busiest airport. This sprawling airport located about 15 miles west of central London, has no fewer than five terminals and is a major hub for British Airways. It is served by hundred of airlines with direct flights to destinations all over the world.
Though it is constantly expanding and modernizing, Heathrow Airport can be a challenge at peak times with long queues both on departure and arrival. Sometimes even the planes have to queue before landing such is the extent of the air traffic.
Facilities are good with a decent choice of shops, bars and restaurants. Distances between terminals, however, can be significant so allow plenty of time for connections. Passengers can move between Terminals 1, 2 and 3 on foot, while buses and trains provide links to Terminals 4 and 5.
There are plenty of options for getting to central London. There are four London Underground stations at Heathrow; the Heathrow Express train runs non-stop to the center while Heathrow Connect will get you to London in 25 minutes. Add to this car rental, bus, shuttle and taxi, and you won't be short of means of transport to get downtown.
London's second airport is London Gatwick Airport (LGW). Though much smaller and easier to manage than Heathrow, this is still a very large airport. British Airways and Easyjet are the airport's main airlines though there are many others serving domestic, European and international destinations, including plenty of good budget flight options. The airport has two terminals, North and South, which are linked by a frequent rail shuttle.
Gatwick is located almost 30 miles south of central London but transport options are good. The Gatwick Express rail link will take you non-stop to Victoria Station, while there are other services that make a few stops along the way. Bus, coach, shuttle, taxi and car rentals are also available to get you downtown.
Thirty miles north-east of central London is Stansted Airport (STN). If you are looking for budget flights this is a good option and it serves plenty of destinations in the United Kingdom, Europe and beyond. It is a hub for budget airline Ryanair, while other budget carriers include Air Asia, Blue Air and EasyJet.
The Stansted Express leaves every 15 minutes for Liverpool Street Station in central London, while you can also travel by bus, shuttle, taxi or rental car.
Finally, the smallest and most convenient London airport is London City Airport (LCY). This is a popular choice with business travelers because of its location just six miles from central London. It serves destinations throughout the United Kingdom and Europe. The small terminal is easy to manage and the London Underground will take you downtown in no time, while there are also buses and taxis available.