Continuity mistake: During the slow-motion sequence, Speedy slams the mallet on the cat's paw and leaves the mallet on the ground when he rescues the mouse. When he puts a stick of dynamite on the cat's tongue, the mallet has gone.
Factual error: While flying across the U.S. before the Atlantic attempt Stewart lands and exits the plane. While doing a quick inspection of the airframe he approaches the engine and puts his hand on one of the radial engines cylinders which would have still been several hundred degrees, so should have resulted in a serious burn.
Continuity mistake: According to one of the characters, the firing squad is drawn from the 3rd Battalion of the 701st Infantry Regiment, the same regiment as most of the other characters. However, all the members of the firing squad (except the officer and sergeant, who are credited characters seen elsewhere in the film) have "710" on their collar patches. This can be seen when the sergeant, who has "701" on his collar patches, is briefing them.
Continuity mistake: When Ned and Ralph are at the clockwork toy, the toy has a lever on its side. But when the toy comes to the cat, the lever is missing.
Continuity mistake: When the St Bernard dog comes to the rescue, he pulls a frozen Sam out of the snow that had fallen on him. But when the dog leaves after drinking the martini, there is no sign of Sam.
Factual error: Montana introduces himself as Sergeant First Class Montana, but his helmet and sleeve insignia shows the rank of Staff Sergeant.
Continuity mistake: When Elmer is stabbing Bugs' hole with his spear, there are rabbit tracks around the hole. But when Elmer says "I'm going to kill the wabbit!" the rabbit tracks have disappeared.
Continuity mistake: When Daffy arrives at the theatre, there is a billboard behind him saying "Bijou Presents on Stage Tonight." But he points to the marquee in the next shot, the words have disappeared.
Revealing mistake: When Speedy Gonzales is watching Sylvester drink Tabasco sauce from the tank that sends him miles into the horizon, watch Speedy's tail: it disappears before the scene ends.
Continuity mistake: When Bugs is trussed like a roast pig, the Tasmanian Devil puts salt and pepper on him and he leaves the salt shaker on the tree stump next to Bugs. But when the Devil unties Bugs later on, the salt shaker has disappeared.
Continuity mistake: When Quackie is at the cafe with Mary, their dog is sitting on the chair between them at the table. But when Inspector Faraway appears, the dog has gone.
Continuity mistake: When the Tasmanian Devil passes by the hamburger stall, you can see there is nothing next to the radio on the counter, but when we see a close-up of the radio in the next shot, there is now a mustard pot and a bottle next to it.
Continuity mistake: When Sylvester is unable to sleep at night, the camera pans in on his eyes and you can see that he has his head on the pillow when this happens, but in the next shot he is lying flat out on the bed.
Continuity mistake: When Hassan is trying to remember the magic word to open the cave door, you can see there is a burrow tunnelling under the entrance, but when we return to Hassan trying to remember the word later on, the burrow has disappeared.
Continuity mistake: The Sergeant (played by Karl Malden) is on leave with his family when the car needs water. His daughter (played by Natalie Wood) gets out and refills the water. During the conversation, Malden is bare headed, then immediately after he has a hat on.
Continuity mistake: The character Sid Sorokin sings the song "Hey There" into a dictograph machine. He then plays it back and sings a "duet" with himself. However, the lyrics and melody at the end of the song are different from what he sang into the machine originally.
Factual error: When Brennan rides into town, behind the stage coach in the back street there is a pick up truck parked.
Continuity mistake: When Jerry hides one of the photographs inside the dress that Joan is making, you can see that the pair of scissors in Joan's sewing basket has a blue handle, but in the next shot it is now coloured red.
Continuity mistake: When the Three Little Bops are performing at the Dew Drop Inn, you can see there is a double bass behind the pigs when they are playing, but when the camera cuts to the piano player, the double bass has disappeared.