Continuity mistake: The buttons on Amos Slade's shirt repeatedly change sides between shots throughout the movie. One example is while Copper and Tod are swimming, when Amos tells Chief that Copper has strayed off again, the buttons on Slade's shirt go from being on the left to being on the right, then back to the left again. (00:21:50)
Factual error: The ship transporting the Great Britain team to France has a marine radar antenna, which did not appear on ships in that decade.