Lead designer behind
Command & Conquer 4: Tiberian Twilight, Sam Bass, takes us for a tour around the Global Statospheric Transport in the behind-the-scenes set tour below. He explains that they decided to use an actual set as opposed to the tried method of green-screens to create a more realistic experience in this iteration.
I think they might have just added fuel to the fire of the video games versus movie arguments. Either way, you get to catch a few glimpses of in-game cut scenes in the walkthrough to see how the set comes to cinematic life.