If they'd had a plot sketched out for the entire series as of the first season (as opposed to making the show up as they went along) they'd have already known/decided that time travel was a factor and would be introduced later in the series and, presumably, wouldn't have said "there isn't any time travel."
unless they were saying, as literally quoted, "I don't think we've shown anything on the show
yet". again, the smoke monster was already teased in the first season, revealed shortly after the quote in the second season. maybe things are different upstate, but for me, that would qualify as having "no rational explanation in the real world that we all function within."
