In addition tothe direct flights from Miami and PR, American also has a direct flight from NY to SKB.

When flying through PR, you want to have plenty of time to make your connections. This is a bit more important when flying from SKB to the US because you enter immigration and customs in PR. You have to claim your luggage there and recheck it after clearing. If your layover is too short, you will not make your connection.

Delta also has a direct flight out of Atlanta, Georgia.