Punta Cana Airport is the airport with most destinations from Dominican Republic and is located where less Dominican lives, that airport is use it mostly by turist, and the Dominicans that use it are no more than 2% or 1%, and we use it because we dont have more options, in my case as I dont have american visa and I can not make conections in USA so I dont have any other option that to go to Punta and take a direct flight to Canada, Now with the new highway from Santo Domingo takes 3 hrs to get to Punta Cana Airport.
Its turns more complicated because you must be 3 hrs before your flight at the airport, plus 3 hours driving, if take a taxi will make you much more expensive your ticket, and if you take a express bus from Santo Domingo is the only way you can save some money on the taxi.
Santo Domingo is the closer airport but only has conections to USA, Central America and South America via Panama with Copa wich usually has very expensive price.
About caribbean Island Insel and Liat you can go to Aruba, Curacao, Saint Marteen, where a lot Dominicans live there and from there you can connect to other island from Santo Domingo
Also you can connect from Santo Domingo to Venezuela, and Bogot?.
To Brasil with Gol from Santo Domingo until March 2015, this airline is moving its operations to Punta Cana.
To Per? with Taca is also moving its operation on January 2015 to Punta Cana.
So Santo Domingo is loosing 2 importants Direct destinations in South America, now to go South America from Santo Domingo will be via Copa with conection in Panama, or with Avianca with Conections en Bogot?.
To Europe till now from Santo Domingo direct flights to Spain, France, Germany and Brussels.
If some body is planning to have Dominican as a Home Base for traveling better move very close to Punta Cana, from there will be very easy to go arround the world with direct flights, 2 airlines conect with Russia, also others to Europe, USA and South America, some other destinations are seasonals.