Commercial flights over at 9am tomorrow morning. No more in or out.
We have to be careful here as the details are confusing and subject to change. As I understand the current situation:
Airlines can decide to stop or limit operations whenever they wish.
Flights that arrive empty for the purpose of repatriating foreigners already in the DR may continue to arrive and perform that function after the borders close at 6am tomorrow.
The DR is not forcing people to stay here against their will. The logistics of leaving is complicated only if airlines and travel charters don't come to pick up their clients.
It is not possible to call an airline and buy a ticket to either come to the DR or leave the DR as no more regularly scheduled flights are set to arrive or depart after the border is closed. Special flights to repatriate foreigners already here may continue to operate for that purpose until all of the foreigners are gone or the airlines give up the effort and pack it in until they resume normal flight operations.
We're on an island so that presents a challenge in coming and going as most people are dependent on a 3rd party to get here. If a citizen or legal resident presents themselves at the border for entry, legally they have to be allowed to enter the country. If such n individual is deemed to be ill, they may be isolated but they can't be turned away.
So, repatriation flights will continue after the borders close tomorrow. How many flights there will be, for how long those flights will be available and where those flights are going is entirely up to the travel companies, the airlines themselves or the govt that is chartering aircraft to collect stranded travelers.