Hi! If you are to fly into St. Louis Lambert International Airport on Southwest Airlines STL Terminal, you would be landing in Terminal 2, and as far as I had checked, you would be using Concourse E with gates E4 to E24. The terminal is easily accessed; it does not take much time to find check-in and security areas and get boarded quickly. And the restaurants and stores do not make you wait for too long. So with Southwest Airlines, in case you're coming from downtown St. Louis, the airport is about 14 miles away and plan early to avoid last minute rushes. Come a little ahead of time, relax, and enjoy a hassle-free journey. Safe travels!