United Airlines, a founding member of the Star Alliance, serves over 350 airports across five continents. In 2026, United continues to operate on a "hub-and-spoke" model, with its primary domestic hubs located at Chicago O'Hare (ORD), Denver (DEN), Houston Intercontinental (IAH), Los Angeles (LAX), Newark Liberty (EWR), San Francisco (SFO), and Washington Dulles (IAD). It also maintains a major Pacific hub at Guam (GUM) and a significant international presence at London Heathrow (LHR) and Tokyo Narita (NRT). Beyond these hubs, United operates at virtually every major city airport in the United States and has a massive network of international destinations, particularly in Europe, Asia, and Latin America. If you are flying to a smaller regional airport, you will likely connect through one of the aforementioned hubs via a "United Express" flight operated by a regional partner.