Frontier Airlines is a no-frills airline, meaning many services such as baggage come at an additional cost. Personal Item: Free (must fit under seat; max 14”H x 18”W x 8”D) Carry-On Bag: Fees vary and are higher if paid at the airport. Max dimensions are 24”H x 16”W x 10”D. Checked Baggage: Also subject to fees; must not exceed 40 pounds unless additional fees are paid. Ov... https://airportsterminalhub.com/airlines/frontier-airlines/frontier-airlines-denver-international-airport-den-terminal/