Southwest Airlines will begin charging customers a fee to check bags. It's a significant change for the budget carrier, which built years of advertising campaigns around its policy of letting passengers check up to two bags for free.

Dallas-based Southwest Airlines made an unexpected announcement: it would be doing away with its bags fly free policy. The policy allowed passengers' first two checked bags to fly free and has been a hallmark of the alternative airline since its founding nearly 60 years ago.

The carrier announced Tuesday that it will begin charging certain passengers to check their luggage on flights, a significant shift at the company long prized by consumers for its perks.