United Airlines Holdings, Inc. is a publicly traded airline holding company headquartered in the Willis Tower in Chicago. UAH owns and operates United Airlines, Inc.

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.