(CNN) — Southwest Airlines has started its mega fare sale that only happens twice a year.
This promotion is designed to fill seats after summer, when travel generally slows down.
The sale includes travel dates starting Aug. 20 and ending mid-December.
You can get a round-trip ticket for under $100 on some flights, but you have to act fast. The sale ends Thursday night.
Southwest launches its next big sale in October.
For more information, click here.

