Roger Christian is the man who literally built Star Wars; he was the set designer on the original movie, before it even got funding:
[George Lucas] didn’t want anything [in Star Wars] to stand out, he wanted it all real and used. And I said, “Finally somebody’s doing it the right way.” All science fiction before was very plastic and stupid uniforms and Flash Gordon stuff. Nothing was new. George was going right against that. My first conversation with him was that spaceships should be things you see in garages with oil dripping and they keep repairing them to keep them going, because that’s how the world is. So we had the conversation and I got hired. I was the third person hired on Star Wars, in fact.
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The Millennium Falcon was difficult, because I had to train prop men to break down jet engines into scrap pieces and then line them all up into different categories and stick them to the walls.
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I told George gingerly one day, “I cannot afford to dress these sets, I can’t get anything made in the studio,” but my idea was to make it like a submarine interior. And if I bought airplane scrap and broke it down, I could stick it in the sets in specific ways — because there’s an order to doing it, it’s not just random. And that’s the art of it. I understood how to do that — engineering and all that stuff. So George said, “Yes, go do it.” And airplane scrap at that time, nobody wanted it. There were junkyards full of it, because they sold it by weight. I could buy almost an entire plane for 50 pounds.