The London airport system is the busiest in the world, with more than 170 million passengers using its six airports in 2017.
In order of size, these airports are Heathrow, Gatwick, Stansted, Luton, London City, and Southend.

Heathrow and Gatwick serve long-haul, European and domestic flights; Southend is used mostly for European flights; Stansted and Luton handle low-cost European and domestic services; whilst London City caters for business passengers to short-haul and domestic destinations.
A small number of long-haul flights depart from Stansted and London City.

The closest airport to the city centre is London City in the Docklands area, about 10 km east of the City of London financial district.
A branch of the Docklands Light Railway links the airport to the City in under 25 minutes.

Two other airports are at the edge of the city but within the Greater London boundary: Biggin Hill, around 23 km southeast of the centre, and London's principal airport, Heathrow, 20–25 km from central London.

Heathrow handles nearly 70 million passengers per annum, making it Europe's busiest airport.
On the western edge of the city in the London Borough of Hillingdon, it has two runways and five passenger terminals, with the £4bn fifth terminal opening in 2008.
It is connected to central London by the dedicated Heathrow Express rail service, the Elizabeth line local rail service and London Underground's Piccadilly line, and is connected to the M4 and M25 motorways.

Gatwick is just under 40 km south of central London in Sussex, some distance outside London's boundary.
With a single runway and two terminals, it handles about 32 million passengers per year from domestic, short-haul and long-haul flights, and is linked to London by the Gatwick Express, Thameslink and Southern rail services, and by the M23.
It is the busiest single runway airport in the world.

Southend is to the east of London, and was developed rapidly to be usable by short-haul passenger flights in time for the 2012 Summer Olympics.
It is connected to London via the A127 road, and an on-airport station with services through Stratford to London Liverpool Street.
Passenger numbers have risen significantly from April 2012 when low-cost flights commenced to 13 European destinations.

Stansted is London's most distant airport, about 50 km north of the centre, in Essex.
With a single runway and terminal, it handles about 20 million passengers annually, mostly from low-cost short-haul and domestic leisure flights.
It is connected to London by the Stansted Express rail service and the M11 motorway.

Luton Airport is about 45 km northwest of London, connected to it by the M1 and Thameslink trains from nearby Luton Airport Parkway station.
It has a single terminal and a runway considerably shorter than the other London airports, and like Stansted it caters mainly for low-cost short-haul leisure flights.

RAF Northolt in west London is used by private jets, and London Heliport in Battersea is used by private helicopters.
There are also Biggin Hill and Farnborough Airfield.
Croydon Airport was originally London's main airport, but was replaced by Heathrow, and closed in 1959.

An airfield at Lydd has been rebranded London Ashford, but currently has little traffic.
In August 2009, Oxford Airport, some 95 km from London's city centre, controversially rebranded itself as London Oxford Airport, while Kent International was briefly called London Manston; it is 120 km from London.

In addition, RAF Brize Norton with direct flights to the Falkland Islands is less than two hours away by car.
Though not generally considered London airports, Birmingham Airport and Southampton Airport have been suggested as alternative airports for London due to the existence of direct rail links serving Central London.
The London airport system is the busiest in the world, with more than 170 million passengers using its six airports in 2017. In order of size, these airports are Heathrow, Gatwick, Stansted, Luton, London City, and Southend.
Heathrow and Gatwick serve long-haul, European and domestic flights; Southend is used mostly for European flights; Stansted and Luton handle low-cost European and domestic services; whilst London City caters for business passengers to short-haul and domestic destinations. A small number of long-haul flights depart from Stansted and London City.
The closest airport to the city centre is London City in the Docklands area, about 10 km east of the City of London financial district. A branch of the Docklands Light Railway links the airport to the City in under 25 minutes.
Two other airports are at the edge of the city but within the Greater London boundary: Biggin Hill, around 23 km southeast of the centre, and London's principal airport, Heathrow, 20–25 km from central London.
Heathrow handles nearly 70 million passengers per annum, making it Europe's busiest airport. On the western edge of the city in the London Borough of Hillingdon, it has two runways and five passenger terminals, with the £4bn fifth terminal opening in 2008. It is connected to central London by the dedicated Heathrow Express rail service, the Elizabeth line local rail service and London Underground's Piccadilly line, and is connected to the M4 and M25 motorways.
Gatwick is just under 40 km south of central London in Sussex, some distance outside London's boundary. With a single runway and two terminals, it handles about 32 million passengers per year from domestic, short-haul and long-haul flights, and is linked to London by the Gatwick Express, Thameslink and Southern rail services, and by the M23. It is the busiest single runway airport in the world.
Southend is to the east of London, and was developed rapidly to be usable by short-haul passenger flights in time for the 2012 Summer Olympics. It is connected to London via the A127 road, and an on-airport station with services through Stratford to London Liverpool Street. Passenger numbers have risen significantly from April 2012 when low-cost flights commenced to 13 European destinations.
Stansted is London's most distant airport, about 50 km north of the centre, in Essex. With a single runway and terminal, it handles about 20 million passengers annually, mostly from low-cost short-haul and domestic leisure flights. It is connected to London by the Stansted Express rail service and the M11 motorway.
Luton Airport is about 45 km northwest of London, connected to it by the M1 and Thameslink trains from nearby Luton Airport Parkway station. It has a single terminal and a runway considerably shorter than the other London airports, and like Stansted it caters mainly for low-cost short-haul leisure flights.
RAF Northolt in west London is used by private jets, and London Heliport in Battersea is used by private helicopters. There are also Biggin Hill and Farnborough Airfield. Croydon Airport was originally London's main airport, but was replaced by Heathrow, and closed in 1959.
An airfield at Lydd has been rebranded London Ashford, but currently has little traffic. In August 2009, Oxford Airport, some 95 km from London's city centre, controversially rebranded itself as London Oxford Airport, while Kent International was briefly called London Manston; it is 120 km from London.
In addition, RAF Brize Norton with direct flights to the Falkland Islands is less than two hours away by car. Though not generally considered London airports, Birmingham Airport and Southampton Airport have been suggested as alternative airports for London due to the existence of direct rail links serving Central London.
Transport in London