Visit Airlines official website for Southwest Airlines book a flight and then go to the Airlines cheap price calendar page. Complete all of the fields in the search engine. You have the option of booking a one-way, round-trip, or multi-trip excursion for your journey. Fill in the origin and end areas as asked. Select the Departure and Arrival Months from the drop-down lists. Fill in your contact information and the number of people you'll be traveling with on the form. Immediately, select the search option from the drop-down menu.