The Airport Express is perhaps the most popular choice for transport to and from the airport.

This is a dedicated airport railway service, and runs on a 12 minute interval timetable. Travel time between the airport and downtown is usually a maximum of 24 minutes.

Airport Express passengers can also take advantage of the fact that there is a shuttle bus provided at both the Kowloon and Hong Kong stations for Airport Express passengers, and this shuttle bus services most major hotels and transport interchanges.
There are also In-Town Check-In Facilities as a complimentary service at both the Hong Kong and Kowloon stations (however, not all airlines and travellers qualify for this. Click here to find out more on these details).

The fare for an adult from the airport to Hong Kong station (one way OR same day return) is HK$ 100, with children 3-11 being HK$ 50. For a closer look at fares, you can always check the MTR website.
Bear in mind that the operating hours for the Airport Express are 0550 to 0115 daily. Again, you might find it prudent to print out the timetable located here.

Pros

• The Airport Express is the most reliable form of transportation should time be a key factor.
• Complimentary shuttle bus service.
• In-Town Check-in Facilities.

Cons

• At HK$ 100 per adult, it is not the cheapest option.
• The views on the trip of Hong Kong are not as spectacular as if you were travelling on the roads, as a portion of the trip is underground.