American Airlines, Northwest and Spirit Airlines fly out of Detroit to St. Thomas. You might get a good deal out of Spirit Airlines. They used to be good in the past but became subject to an increasing number of customer complaints that did some serious damage to their reputation over the last couple of years. You won't get a direct flight out of Detroit to St. Thomas as far as I know so you will have to be prepared for a stopover in either Atlanta, Miami or Puerto Rico. It will be difficult to get pricing or schedules for President's week 2010 this early out, but if you go to the DTW airport website you can check the various Airlines and see what their current 2009Presidents week schedules are like to at least get an idea of which airlines fly to St. Thomas via which hub airports.