Southwest Airlines is once again extending its sale on fall and winter flights.This time around, travelers have until Thursday, October 10 at 11:59 p.m. PT to book the discounted fares, which start as low as $49 one-way. Trending Now Fares are valid for continental U.S. travel October 22, 2019, through March 4, 2020; travel to/from San Juan, Puerto Rico October 29 through December 5, 2019, and January 13 through March 5, 2020 and international travel October 29 through December 11, 2019, and January 7 through March 5, 2020.Fourteen-day advance purchase is required for travel within the continental U.S. while a 21-day advance purchase is required for international travel and travel to and from San Juan. Blackout dates also apply around the holidays.Discounted seats include flights between Las Vegas and Los Angeles for under $60 one-way and Dallas and Denver for less than $200 roundtrip. Travelers can also fly between Fort Lauderdale and Cancun for as little as $118 one-way.Contact your travel agent or visit Southwest's website to filter flight deals by your departure city. Let's block ads! (Why?)