Frontier Airlines

Frontier Airlines is a United States ultra-low-cost carrier headquartered in Denver, Colorado, operating under a name previously used by an earlier, unrelated Denver-based airline that ceased operations in the 1980s before the current company relaunched it in the mid-1990s. Frontier is best known for the large colorful wildlife illustrations painted on the tails of its aircraft, each representing a different animal species, and for a business model built around low base fares with charges for most additional services, similar to fellow US ultra-low-cost carriers Spirit and Allegiant. Denver International Airport serves as Frontier's primary hub, and the airline has expanded a route network connecting mid-sized and leisure-oriented US cities that are often underserved by larger legacy carriers.