Los Angeles, CA LAX to Denver, CO DEN flight with United

United Airlines is one of the USA’s leading carriers, operating both domestic and international routes. For your next trip, you can choose from Economy, Premium Economy, and Business Class fares.

Frontier Airlines is a major American ultra-low-cost carrier headquartered in Denver, Colorado, operating flights to over 120 destinations across the United States, Caribbean, Mexico, and Central America. Known for its "Low Fares Done Right" philosophy, Frontier focuses on offering affordable travel by allowing passengers to choose and pay only for the services they need, such as seat selection or baggage. The airline is also recognized for its commitment to fuel efficiency, claiming to be "America's greenest airline" due to its modern, lightweight aircraft and operational practices. A distinctive feature of Frontier is the animal featured on the tail of each aircraft, highlighting North American wildlife.

Spirit Airlines is an American ultra-low-cost carrier, headquartered in Dania Beach, Florida, operating scheduled flights throughout the United States, the Caribbean, and Latin America. Known for its distinctive bright yellow planes, Spirit's business model traditionally focuses on offering low base fares by unbundling services, allowing passengers to pay only for the amenities they choose, such as baggage and seat selection. As of August 2024, Spirit is evolving its offerings, introducing new fare tiers like "Go Big," "Go Comfy," "Go Savvy," and "Go," which include various bundled perks such as wider seats, extra legroom, priority boarding, and in-flight refreshments. Spirit was the seventh largest passenger carrier in North America as of 2023.