Those arriving from the U.S. are now going to be subject to the same strict rules as those arriving from India, Indonesia, etc. That means no home quarantine: hotel bookings must be shown. And it means a PCR test no more than 72 hours before departure. Together with a letter from the local government certifying the lab is authorised to do the test. I suspect that last item will in many cases be impossible to obtain, certainly in a rush before departure. As a practical matter, I suspect this will cut off travel from the U.S. And it may affect outbound traffic as well, making return much more of a hassle. All of which may lead to flight reductions.
https://www.coronavirus.gov.hk/eng/h...sk-places.html