Could a German/Italian naval/aerial assault have toppled England in the 40s?

Germany's greatest ally was Italy. Mussolini was all for an attack on England, but Hitler, the dumba$$ he was backed out. Italy had a pretty decent Navy and excellent destroyers, plus their air force. Had England been overrun, the U.S. would have almost no shot at assault Europe. Had Hitler not ordered the ME 262 into a bomber for missions over Russia and used it as a jet fighter, which it was, well, history would be very different.