Was in Macau last October and flying out of Hong Kong. Noticed they had an airport link, thinking it was just a normal type bus service. Was totally impressed at the end, that checking in for the bus in Macau was a full airport style check in, passport, ticket and luggage. Bus transfer is technically 'Airside' transfer.
Transfer was about 1.5 hours at HK$140, so about £14:00.