Revealing mistake: A scene in which a group of soldiers appears to be running uphill was obviously filmed with a tilted camera because all the trees in the background are leaning at a 65-degree angle.
Factual error: Abbott and Costello have inadvertently enlisted in the Army but anyone weighing 240 pounds or more will be rejected. When Costello steps on the scale, the Army physician tells him, "You're in the Army. You made it by two ounces." Medical scales at that time (1941) showed weight in whole pounds only and did not show ounces.