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Sadly, I think they are pretty similar. Big air is so much less about style now and much more about spinning/flipping. Granted, you aren't rigin in the air like an aerialist, but the training is very similar. If you disagree, look at the King of Style, or any other big air contest that isn't actually a big jump. Doubles are still being done, and although they aren't bad looking, they are far from stylie.
And in regards to the discussion that aerialists can't ski, they essentially ski just as much as big air skiers need to. Drop in, hit a jump, flip and spin, then land. Its very, very similar.