This is a blink-and-you'll-miss-it sale.
Purchase tickets on Southwest Airlines by the end of the day on Thursday, September 24, for a flight between now and November 15, and you will have the right to bring a companion for free every time you fly between January 6 and February 28, 2021. (Note: the deadline was extended to end of day on Friday, September 25).
When the time comes to book your 2021 flight—or flights!—for you and your companion, you'll just have to pay taxes and fees (starting at $5.60) on the other person's tickets.
Not all gateways are included in the sale, so read the fine print before biting.
Also, the promotion is only open to Southwest's Rapid Rewards members, but that shouldn't keep anyone away—the program is free and easy to join on the airline's website.
Click here if this interests you, but don't delay: This promo is a short one!