Traveling on a budget with Frontier Airlines? Make sure your bag meets the Frontier Personal Item Size limit to avoid additional fees. Frontier Airlines Personal Item Size is 14" x 18" x 8", and it must fit under the seat in front of you. Acceptable personal items include laptop bags, small backpacks, and purses. If your bag is too large, it will be categorized as a carry-on, requirin... https://www.airlinereservationwindow.com/frontier-airlines-personal-item-size-limit/