Operating out of Terminal 1 at St. Louis Lambert International Airport (STL) is United Airlines. United Airlines At STL Terminal The terminal has several amenities, such as a United Club lounge, self-service kiosks, and ticket counters. Near the main entrance are check-in counters where passengers can get assistance from customer service. Before you get to the gate areas, there are security checkpoints. There are places to eat and shop all across the terminal, so you can pass the time comfortably before your trip. Real-time information about flight updates and adjustments can be seen on the United app and airport monitors.