I've seen David Copperfield live, one of the greatest shows I've ever attended! Magic is cool 
He actually sued a French magician who duplicated that setup.
Copperfield “buys” his illusions from other magicians and then usually modifies & personalizes them with music and costuming.
Then, he gets a copyright on the whole thing, and often owns the exclusive rights to the effect and/or performance.
A magician buddy of mine in OH knew the guy who created the flying apparatus.
He wouldn’t tell me how much DC paid for the plans - maybe he didn’t know himself - but back in the day Copperfield would easily drop $20,000 and up for some of those things.
Even the little close up effects he performed, he paid good money for.