Hi Norm ... Carol is right about using two airlines. Southwest is pretty reliable, but if there's a long weather delay, etc. the anxiety isn't worth it. But, if the price fits here's another idea to consider. Fly Southwest from St. Louis to FLL the day before and book a hotel room near the airport. There are some very nice hotels in the vicinity. Relax and enjoy a nice dinner that evening (i.e., Tropical Acres!). Then take Jet Blue the next morning to St. Maarten. You get an extra day on vacation and you don't need to worry about missing your second flight. This is what a lot of people do when taking a cruise out of Port Everglades, FL. Just a thought.