Frontier Airlines Save up to $20◊ with today’s promo code when booking your Frontier Airlines flight. Book travel to any destination Frontier serves, including Phoenix, Austin, San Francisco and Las Vegas. Frontier now also flies to Provo, Utah and Knoxville, Tennessee. While a low-cost carrier, passengers still enjoy top quality service and amenities. Frontier rewards its frequent flyers with the EarlyReturns mileage program, offering great perks and competitive redemption levels. Through its hub at Denver International Airport, Frontier Airlines flies to 76 destinations in the U.S., Mexico, Costa Rica and the Dominican Republic. Incorporated in 1994, Frontier’s fleet of aircraft has grown to 73 Airbus models, and in 2007 was designated by the United States Department of Transportation as a major airline. Frontier Airlines has an excellent maintenance record, winning the FAA Diamond award ten years in a row. In 2010 Frontier’s parent company, Republic Airways Holdings, announced the merger of Frontier and Midwest Airlines under the Frontier Airlines name.