It’s a season of savings for travelers looking for a deal on airfare this fall and winter. Southwest Airlines' «September Travel Included» sale includes flights for fall booked before Aug. 24. The fare sale is valid on most flights between Sept. 19 and Feb. 14, 2024. Flights to San Juan, Puerto Rico and the islands of Hawaii are valid until March 6, 2024. Travel + Leisure looked into the fare sale and found discounts on popular routes including: