Iran says the fake ship is being built to be part of a movie centered on an Iranian airliner that was shot down by an American ship.
The USS Vincennes fired two missles at Iran Air flight 655 in 1988 after it mistook the plane for a fighter jet it thought was part of an attack on the ship.
290 passengers and crew were killed when the plane went down.
Navy spokesman Jason Salata didn’t sound concerned when he told Reuters "we know it's not an actual aircraft carrier.” But he went on to say, “it's made to look like one of ours, but makes us wonder, what is it all for?"
Salata said the prop is complete with planes on the deck but is only 2/3’s the length of an American nuclear-powered ship.
Pictures show the fake painted with the number 68, the ID of the USS Nimitz.
Satellites spotted the “carrier” in port leading US officials to ask about it. That lead one Iranian website to complain “the issue has turned into a good excuse for another wave of hype against Iran."