Now, the government has revealed plans to allow Hong Kong residents to return from mainland China, subject to a restricted quota and tests, without the need to quarantine at all. Two border checkpoints will reopen to carry this out: the Hong Kong-Zhuhai-Macau Bridge and Shenzhen Bay.
This might help the return of flights to the mainland at least. Once they open the borders through the checkpoints the next move will be the airport. I can't see it working as far as keeping the number of cases down. It is still better than a complete lockout of all resulting in no flying at all.