Frontier Airlines is a low-cost airline based in the United States, known for offering affordable flights to various destinations. Founded in 1994, it operates from its main hub at Denver International Airport and serves numerous cities across the country and some international locations. The airline focuses on providing basic air travel services, allowing passengers to customize their experience by adding options like checked baggage and seat selection for an additional fee. This business model helps keep ticket prices low while catering to budget-conscious travelers.