Yellow Submarine (1968)

Continuity mistake: During the song "Hey Bulldog," before the song starts the dogs are on a leash barking. When the song starts and the dogs stop barking, the leash disappears.

Paul: Look, it's a school of whales.
Ringo: They look a little bit old for school.
Paul: University then.
Ringo: University of "Wales."
John: They look like drop outs to me.

Trivia: The original Beatles did not voice themselves in the film. They only showed up at the end and they sing the songs.