In 2018, United Airlines had the fourth highest domestic market share among U.S. airlines, accounting for roughly 15 percent of the market. Its main competitors are Southwest Airlines, American Airlines and Delta Air Lines. United currently operates out of nine airline hubs with main hubs in Chicago, Denver, Houston, Newark and San Francisco. The others are located in Guam, Los Angeles, Tokyo, as well as in Washington, D.C. Chicago’s O’Hare International Airport is United’s largest hub with over 10.5 million passengers constituting the amount of recorded passenger traffic in 2018.
In the fiscal year of 2018, the number of passengers boarded by United Airlines amounted to more than 158 million revenue passengers. United generated over 888.7 million U.S. dollars in revenue from passenger baggage fees in 2018. The airline's parent company, United Continental Holdings, reported operating revenue of around 41.3 billion U.S. dollars in 2018 and the company is a founding member of the world's largest airline alliance, Star Alliance.
United Airline’s regional service is currently operated by independent carriers under the brand name United Express. United Airlines has continued to be among the list of favorite airlines among United States travelers.