Absolutely! Frontier Airlines World Mastercard® credit cardmembers can use the free checked bag benefit when checking in via the Frontier Airlines mobile app or at FlyFrontier.com. If checking in at the airport, visit the check-in counter to have your free checked bags processed; a $25 fee may apply if talking to an agent. Unfortunately, airport self-serve kiosks won’t be able to process your free checked bags at the moment.