Didn't he say it was some sort of radio control?
Quote Originally Posted by HOOTERS
They couldn't land a man on the moon
Yes they could, they just abandoned the idea.

I always pictured it like a virtual reality suit type of thing. Reeves was in some hidden room walking and moving around to get Cait Sith to move, and the giant Moogle suit always mimicked what Cait Sith did, so I suppose their circuits were connected.