Frontier Airlines is stepping up its game. The airline announced Tuesday via press release that it will offer customers a free checked bag on select flights this summer.

Last week, Southwest Airlines announced an end to its long-time policy of two-free checked bags. Frontier officials say customer response will help determine if its free service will become permanent. The promotion is good for Frontier flights departing between May 28 and August 18. You'll need to use the promo code "Free Bag" to get the perk.

Frontier Airlines is offering a complimentary checked bag, carry-on, seat selection, and flight changes for nonstop flights booked by March 24. This promotion follows Southwest Airlines' recent announcement to end its free checked bag policy, a move that has been met with resistance from some customers.