Frontier Airlines is the only major U.S. airline that offers low fares. We have the best deals on flights, vacation packages. Book your next flight with us and experience a whole new way to fly! Frontier Airlines is a U.S. based, ultra-low-cost airline. We offer the cheapest flights and travel packages to destinations in US. Frontier Airlines is a budget-friendly airline that offers cheap flights and travel deals. Their travel packages are especially popular, and they offer a variety of destinations to choose from. If you're looking for a bargain on your next vacation, Frontier Airlines is the perfect option!