United Airlines operates from Terminal at St. Louis Lambert International Airport (STL), primarily using Concourse A. United Airlines At STL Terminal the terminal offers multiple check-in options, including counters and self-service kiosks. After check-in, passengers proceed through a centralized security checkpoint, with TSA PreCheck available for eligible travelers. Although United does not have its own lounge at STL, the terminal features a range of dining and shopping options. For ground transportation, passengers can choose from rental cars, taxis, ride-sharing services, and the MetroLink light rail, which connects the airport to downtown St. Louis and other areas.