London has 6 airports: Heathrow, Gatwick, Luton, London City, Stansted and Southend. Most international flights go to Heathrow.
Heathrow is the largest airport in Europe and is located approximately 25 km west of London. Heathrow has 5 terminals: terminals 1,2 and 3 are located in the northern part of the airport, terminal 4 is on the south side and terminal 5 on the west side.
Heathrow is the only airport connected to the underground network. Heathrow has 3 underground stations: Terminal 2 and 3, Terminal 4 and Terminal 5 which are connected to the Picadilly Line. A drive to Piccadilly Circus takes approximately 50 minutes.
the Heathrow Express runs to and from London Paddington station every 15 minutes between 05:00 and 24:00. The trains stop in front of the station at terminals 2 and 3. The journey time is approximately 15 minutes.
The Elisabeth Line is a slightly slower train service and also runs to London Paddington station. The journey takes about 20-25 minutes. The advantage of the Elizabeth line is that you can pay with the Oyster Card.
–> trip planner Heathrow https://www.heathrow.com/transport-and-directions/getting-to-central-london/journey-planner
London Luton is located about 50km north of London and is frequently served by EasyJet.
about a kilometer from the airport is the Luton Airport Parkway station. Trains run from this station to London St Pancras, the journey takes approximately 30 minutes.
A special shuttle bus runs from the airport to the train station. The Luton Dart (Direct Air Rail Transit) will open in 2022, taking you from the airport to the train station within 5 minutes.
–> trip planner London Luton https://www.london-luton.co.uk/to-and-from-lla/going-south-beyond-london
Stansted Airport is located approximately 40 miles northeast of London. It is the 3rd largest airport in London, after Heathrow and Gatwick.
there is an excellent rail connection between the airport and Liverpool Street station, the Stansted Express. The train station is 2 floors below the airport terminal. This train runs every 15 minutes during rush hours and every half hour outside rush hours, the journey takes about 50 minutes.
Liverpool Street Station underground station is linked to the train station.
–> Stansted Express trip planner https://www.stanstedexpress.com/travel-information/train-times/
Londen City Airport
London City Airport is known as the airport in the center of London. It is a small airport. The big advantage is that you are immediately in London after landing.
Dockland Light Railway
London City Airport is connected to the Dockland Light Railway (a kind of overground tube), which runs every 8 to 15 minutes to Bank and Canning Town tube stations