United Airlines’ primary hub, Washington Dulles International Airport (IAD). United Airlines IAD Terminal offers a wide range of facilities and services to guarantee a convenient and hassle-free travel experience. With an additional set of gates in Terminal B, United Airlines mostly operates out of Terminals C and D. Travelers flying with United Airlines will find the airport to be a handy gateway thanks to its state-of-the-art infrastructure, well-run operations, and extensive selection of services.