From the airport

Besides being one of the world's classiest airports, Hong Kong Airport has an excellent transport network.  Both terminals are connected by a four level Ground Transportation Network. One can interconnect by the Airport Express trains, franchised buses, hotel coach shuttles, mainland coach services, taxis or just hire a car from the airport itself. Limousine services provided by hotels or travel agents are available from the special lounge - T 1. Baggage trolleys are easily available everywhere.

The Airport Express Train operates from 05:15 to 00:48. It is super fast and efficient with dedicated service for air passengers and guests. There is a train every 12 minutes. One can check in at the Hong Kong Central or Kowloon stations. There are enough shuttles to connect to this train.

Fares are as follows:

Hong Kong station: Same day one way HK $ 100, return HK $ 180
Kowloon :                  Same day one way HK $ 90  , return HK $  160
Tsing Yi Station:       Same day one way HK$ 60  ,   return HK $  110

Exp station                Same day one way HK $ 5

Child (3-11yrs) and senior citizen is half the adult fare.

Cheaper options (HK$ 5) though longer are the number of bus options.
Taxis are available as per listed colors and are in the range of HK$ 35 to HK$ 45.