United Airlines operates one of the largest airline networks in the world, flying passengers and cargo across an extensive domestic and international route network built around hub airports in cities like Chicago, Denver, Houston and San Francisco. Airlines are a capital-intensive, cyclical business where profitability depends on managing fuel costs, labor expenses and capacity, the number of seats flown, relative to passenger demand at any given time. United's international route network, particularly across the Pacific and Atlantic, gives it meaningful exposure to global business and leisure travel demand beyond just domestic U.S. flying. The airline industry's profitability has historically been volatile, sensitive to fuel price swings, economic cycles affecting both business and leisure travel, and periodic industry-wide capacity additions that can pressure ticket prices when airlines add more seats than demand supports.