Packing for a Frontier Airlines flight? Understanding the Frontier Air personal item size rules can save you from unexpected fees. The airline allows one free personal item, but it must fit under the seat. Many travelers assume their Frontier Airlines personal item size is fine, only to face extra charges at the gate. Check the personal bag size Frontier permits before you travel to avoid issues. Whether it’s a small backpack, purse, or tote, make sure it meets the dimensions for personal item Frontier allows. Save money and pack wisely! #FlyLight