Are you trying to maximize your carry-on with Frontier Airlines? The key is understanding the Frontier Air Personal Item Size restrictions. Frontier allows passengers to bring one personal item on board, which must fit under the seat in front of you. The ideal dimensions for this personal item are 18″ x 14″ x 8″ or less. A compact, well-packed personal item can help you avoid the need for a paid carry-on. Make sure your backpack, purse, or small bag meets these size requirements, and you’ll travel comfortably without the risk of paying additional fees for oversized luggage.