Southwest Airlines will be changing its baggage policy this spring. Here's what to know before your next flight.

Southwest Airlines said Tuesday it will start charging most passengers for checked baggage, ending a longtime free-luggage policy that the company had touted as an important differentiator as recently as last fall. The new policy, which follows other quirks recently discarded by the idiosyncratic airline, applies to flights booked starting May 28.

Southwest will start charging customers to check bags, launch basic economy tickets in a bid to drive up revenue.