How to get to Hong Kong airport from the city early in the morning or late at night

If you have an early flight or late flight at the Hong Kong airport, chances are you won't be able to take the express train which starts at 5:50 and ends at 1:15
Your options are:
Taxi: about HK$300+ from Tsim Sha Tsui (TST), 30min
Uber: cheaper! about HK$250+ from TST, 30min
Night bus: N21 from TST (Star Ferry) - Airport
the stop I took the bus from is near the famous Chungking mansion (the opposite side) on Chatham Road South outside The Kowloon Hotel

Cost: HK$23
it was super long ride to the airport almost 80minutes because there are many stops. So make sure you reserve enough time. You can sleep on the bus as the airport is the last stop, just keep close your belongings
See Departing schedule and stops info in image below

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