Check - in Requirements Passengers and their baggage must be checked in at least 45 minutes before departure for domestic flights and 60 minutes for international flights. Government - issued photo identification is required for all passengers. Passengers traveling across any international boundary( 边界 ) are responsible for obtaining all necessary travel documents. Passengers may be denied boarding if travel documents are not in order. When check - in requirements are not met , a passenger may be separated from his / her bag. Frontier Airlines will gladly hold the bag in the destination baggage service office for pick - up at the passenger ’ s convenience. Passengers must be at the gate 20 minutes before departure for boarding. Free Baggage Allowance for Each Ticketed Passenger Frontier Airlines Inc. will accept , per ticketed passenger , two free checked bags not to exceed 62 inches and 50 pounds per piece — one carry - on bag and one personal item (purse, laptop, etc.). NOTE : A ticketed passenger may check one carry - on bag if it is within established limitations. All carry - on items must be put under a passenger seat or in a shared overhead compartment( 行李舱 ). Excessive( 超重 ) Baggage Charges An excess charge will be made for each piece of baggage over the free allowance and for each piece of over - sized or over - weight baggage.