I have offline jumpseated on American Eagle from SXM to SJU. Sometimes it is tricky with the ticket agents (the pilots are glad to have you). As long as you have an agreement with AE, it should work. If you do, check to see if it is an international jumpseat agreement, because then you will have no problems. However, I would check into ZED or ID90 tickets, also. I always carry some as a backup. Also, I don't know if Caribbean Star/Sun or Winair fly to your destination, but they are very accomodating to jumpseaters, with or without an agreement.