What terminal is united at george bush airport? Terminal C is where United operates most of the time. It is clean, orderly, and has plenty of places to dine and sit. I was pleased to see that everything was quite efficient, from check-in to boarding. If you head straight to Terminal C on a United flight, you should be alright. This made my travel a lot less worrisome. One of the easiest airport experiences I've ever had, without a doubt!