S1·E18 All Fall Down

The Omni lands Bogg and Jeff in New Jersey, 1938, where they find Joe Louis ready to quit boxing while preparing for his rematch with Max Schmeling. Bogg becomes his sparring partner to convince him otherwise, but a lucky punch on his part manages to knock out Louis and even further convince him to quit for good. Hostile fight-ring workers dont' take kindly to Bogg, and he and Jeff escape to a 747 in 1970. Jeff ends up piloting the craft when terrorists knock everyone else out with gas. After a safe landing, the duo return to 1938, where they put Louis on a Rocky-style training regimen. Louis ends up beating Schmeling and history is back on track.