One complimentary personal item per traveler is allowed by Frontier Airlines; however, handles, wheels, and straps must not be larger than 14 inches in height, 18 inches in width, and 8 inches in depth. Under the seat in front of you, this item must fit completely. Laptop bags, totes, purses, and little backpacks are typical examples. https://airlineterminalservice.com/blog/frontier-airlines-personal-item-size/