It is a really smart move on United's part.
Hong Kong is definitely suffering from lack of service to the US. CX and UA are the only airlines with nonstop flights between HKG and USA.
I presume United will want to resume more flights to Mainland China, but because of air rights issues and possibly political too, United can't really do much. Going to Hong Kong is a smart move and many Mainland passengers have flown to Hong Kong for onward flights to Mainland now.
With double SFO flight and a new LAX flight, I hope United will reopen its Hong Kong lounge soon too.
Good news for HKG passengers but I still don't see the price will reduce much!
Carfield