Ironically the only people I have seen that seriously think this are Trump supporters. Although to be more accurate they think he is a forerunner to the "Messiah" but that doesn't stop them from talking about how Trump might be the Jewish "Messiah"
A false Messiah by definition is an antichrist.
But just to make it clear: I don't think Donald Trump is the Antichrist. But I do find it horrifying to see his supporters get excited at the idea that he might be either a false messiah, or a forerunner to a false messiah.