Just an update regarding helicopter flights and transfers.
Companies that offer this service are NOT located in Dubrovnik. Example, there is one company located in Zagreb that offers helicopter flights around Croatia. But, if you plan to be picked up in Dubrovnik they will charge for the flight from Zagreb to Dubrovnik, your own flight to your destination, and again for the return from Dubrovnik to Zagreb. This means that the price is very high, I would recommend this only to those that really need this service or those where the price is not relevant.
Another nice way to travel around, if you have the time, is by ferry, more information at: http://www.dubrovnik-online.net/english/transportation_sea.php