I wasn't expecting same-day return fare for Airport Express. I see $90 from HKG to Kowloon for a single and $160 for the return. Surely they don't' expect you to return the same day?

I did consider the Airport Express tickets with the 3-day pass but that's only valid on the MTR right? So if I want to use the Star Ferry or buses, that wouldn't work?

How do you pay fares on the bus with the OC? Fares vary depending on the distance, it appears. So do you have the OC read when you board and when you exit the buses? For instance, I may take the bus from TST to Aberdeen or from Central to Aberdeen/Stanley. Or another bus between Aberdeen and Stanley.

Also, can the OC be used to pay for the ferry to Lantau, the buses on Lantau Island, the cable car on Lantau? And the MTR back from Lantau to TST?