Atlanta, GA ATL to Denver, CO DEN flight with United

United Airlines, established in 1926, is a major U.S. airline headquartered in Chicago, Illinois. Operating an extensive domestic and international network, United serves more destinations than any other airline, connecting travelers across six continents. The airline's eight hubs include Chicago–O'Hare, Denver, Houston–Intercontinental, Los Angeles, Newark, San Francisco, Washington–Dulles, and Guam. As a founding member of the Star Alliance, United offers a comprehensive range of services, including regional flights through United Express, catering to both leisure and business travelers. The airline is committed to sustainability, investing in sustainable aviation fuel and innovative technologies to reduce its environmental impact.

American Airlines is one of the largest airlines in the world, connecting travelers to hundreds of destinations across the United States, Latin America, Europe, Asia, and beyond. Operating from major hubs such as Dallas/Fort Worth, Miami, and Charlotte, American offers a wide range of travel options. Passengers can choose from Economy with affordable fares, Premium Economy with extra space, or Business and First Class featuring flat-bed seats, premium dining, and lounge access. With a modern fleet and membership in the oneworld alliance, American Airlines combines global reach with comfort and reliability.

Alaska Airlines, headquartered in SeaTac, Washington, is a major U.S. airline and the fifth-largest in North America by scheduled passengers carried as of 2024. Along with its regional partners, Horizon Air and SkyWest Airlines, Alaska Airlines operates a route network primarily connecting cities along the West Coast of the United States, including Alaska and Hawaii, to over 100 destinations in the contiguous U.S., the Bahamas, Belize, Canada, Costa Rica, Guatemala, and Mexico. The airline is a member of the Oneworld alliance, offering passengers access to a broad global network. Alaska Airlines is known for its customer service and loyalty program, Mileage Plan, and offers First Class, Premium Class, and Main Cabin seating options. The airline's primary hub is Seattle-Tacoma International Airport. In 2024, its parent company, Alaska Air Group, acquired Hawaiian Airlines.

PSA Airlines is an American regional airline and a wholly-owned subsidiary of the American Airlines Group, operating exclusively on behalf of American Airlines under the American Eagle brand. Headquartered in Charlotte, North Carolina, PSA Airlines operates over 800 daily flights to nearly 100 destinations across the United States. The airline maintains an all-jet fleet consisting of Bombardier CRJ700 and CRJ900 regional aircraft. With a team of over 5,000 employees, PSA Airlines plays a significant role in connecting smaller cities to major hubs within American Airlines' network.

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."