Southwest's weekly 3-Day Sale is valid through June 10, for travel every day except Fridays, Saturdays, and Sundays. Fares require a 14-day advance purchase, and all tickets must be booked by 11:59pm PT, March 25.
They call these fares "breathtaking" and they surely are, but not in a good way. Detroit to Milwaukee for $298 round-trip!?
Fares aren't quite as low as we've seen in previous Southwest weekly sales, but still better than what you'll find from other carriers along many of these routes.
Avoid blackout dates from May 27 through June 1, when you'll pay even more.