Southwest Airlines starts Mega Fare Sale

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 August 20th and ending in mid-December.

You can get a round-trip ticket under a $100 on some flights–but you have to act fast–the sale ends Thursday night.

Southwest launches its next  big sale in October.