New build idea

So I've had a idea to make a giant floating platform kinda like a flying aircraft carrier but I'm wondering how I should do it. I'm think it could be like a hang out area or a neutral zone and I want to make it big for all sizes of planes but here's my problem...

I don't know how I'm gonna make it float

Something as big as what I'm going to build will most likely be really big so if any thoughts

(Also P.S. I'm sorry about the shredder thing I'm planning on leaning away from shredders)

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