From Heathrow Airport there are 3 options:
A fast train (20 mins to Paddington station)
A slower train (30 mins to Paddington station)
The Piccadilly Line Undergound train (50 mins to Knightsbridge station).
From Gatwick Airport the trains go to Victoria station (35 mins).
From Luton Airport the trains go to Kings Cross/St.Pancras station (40 mins).
From Stansted Airport the trains go to Liverpool Street station (not shown on map).
Trains from Paris and Brussels arrive at Kings Cross/St.Pancras station.