Try to avoid travelling during the rush hours. London has four airports none of which is commonly referred to as London Airport. The largest is Heathrow . It has four large terminals, two tube stations on the Piccadilly Line, and a railway link to Padington Station. It is the world's busiest international airport with the largest variety of airlines and flights.
Taxis are expensive.
Gatwick is the city's second airport. Many charter flights leave from here as well as long haul. This has two terminals and its own railway station. It is reached by train from Victoria Station. Stanstead is the third airport and is a train ride away from Liverpool Street Station.