Frontier Airlines

Frontier Airlines is a low-fare carrier that flies an Airbus A320 family fleet to roughly 120 destinations in the U.S., the Caribbean, Mexico and Central America. The airline is known for low base fares with optional extras such as bags and seats, and it runs a loyalty program called Frontier Miles.

Flights, hotels, rental cars and activities can be booked through the airline's website, which also handles check-in, flight status and bag and seat purchases through its app. Its headquarters are in Denver, Colorado, and this listing's address is in Middletown, Pennsylvania. Children 14 and under can fly free on qualifying flights through its Discount Den travel club.