[Dark Raven]

I don't think the Helicarrier is a problem. In Star Trek, they had the Enterprise (or whichever ship they had for a series) on a weekly basis, as well as all the recurring alien ships.

Half the time anyway, they'll probably just be filming the interiors (they'll have a set for that) or it might be on the flight deck, in which case it would look like a normal aircraft carrier (which they could use, unless they also have a set for that too).