You can book Southwest no problem. As long as they take the credit card you're good to go.They are as good as anyone for such a short flight.

The one thing you need to remember is to check in 24 hours in advance if you want to get an "A" boarding pass. Southwest does not asiign seats but gives out boarding passes in an A, B, C configuration. A B boarding pass will still get you an aisle or window seat. It's the C boarding pass that you can wind up with a middle seat. But it's a short flight.