Character mistake: On the sign outside Dr I.Q. Hi's headquarters, the word "Stratosphere" is spelled "Stratopere."
Duck Dodgers in the 24 1/2th Century (1953)
1 character mistake - chronological order
Continuity mistake: When Duck Dodgers claims Planet X with his flag, you can see there is nothing next to him, but when Marvin the Martian comes along and makes his claim, an "X" tree has suddenly appeared.