United Airport Shuttle

United Airlines, Inc. is a major American airline headquartered at the Willis Tower in Chicago, Illinois. United operates an extensive domestic and international route network across the United States and all six inhabited continents primarily out of its eight hubs, with Chicago-O'Hare having the largest number of daily flights and Denver carrying the most passengers in 2023. Regional service is operated by independent carriers under the brand name United Express.

Southwest Airlines Co. is a major airline based in the United States operating with a low-cost carrier model. It is headquartered in Dallas, Texas, and has scheduled service to 121 destinations in the United States and 10 additional countries.