O Captain! My Captain! - S4-E11
Other mistake: Barry climbs up on the desk and comically recites the "Oh Captain my Captain" refrain, which is in reference to the finale of Dead Poet's Society, which came out in 1989. An actual time jump forward, that would make him 20-something, which he isn't. And makes no sense for the episode, which is still set in the mid-80s.