Factual error: It is impossible for a stream of burning jet fuel to follow a plane through snow and catch up. Not only is jet fuel extremely hard to ignite, almost as soon as the plane was off the ground the fuel stream would be too dispersed for the flame to climb up into the tank, and even if not it wouldn't burn fast enough to catch the plane.
Continuity mistake: In the first film, it is mentioned several times that Kevin is 8 years old. However, in this film it is stated that he is 10. When his parents are in the Miami airport security office, they say that he was left alone last Christmas. That would make him 9. Both films take place the same days, from about three days before Christmas until Christmas morning, so even if Kevin is born around Christmas time this is still a mistake.
Continuity mistake: The train that transports The Haynes Sisters and Wallace and Davis from Florida to Vermont is shown as being of the Atchison, Topeka and Santa Fe Railway in one sequence, and of the Southern Pacific Railroad in another. Neither railway ran on the east coast of the U.S.
Other mistake: When Jack first arrives in Christmas Land he doesn't know what is falling from the sky (snow) but he somehow knows that the children are throwing snowballs.
Visible crew/equipment: When a gremlin attacks the Mum from a Christmas tree, and the tree falls on top of her, you can clearly see a member of the crew with eyeglasses, wearing a red shirt, standing behind the tree pushing it forward on top of her. (00:54:30)
Other mistake: At the end of the show when the misfit toys are being delivered, the elf in Santa's sleigh gives an umbrella to each of the misfits so they can glide down with the exception of the bird, who jumps off, apparently forgetting that he is a misfit toy and can't fly; as he stated earlier in the show, he can only swim.
Revealing mistake: Riggs handcuffs himself to the depressed businessman. They jump off the building but they're not handcuffed to each other anymore. They used plastic cuffs which could separate during the stunt in case anything went wrong. They break just as they jump, so they grab each other's hands to stay in contact. After they land the cuffs are attached again. (00:31:00)
Visible crew/equipment: After Mortimer's comment that Billy Ray has probably been stealing since he could crawl, when it cuts to the two officers opening the squad doors to place Billy Ray at the back of the vehicle, the barndoor set lighting is visible over the squad car at the top right corner of the screen. (00:18:25)
Continuity mistake: When Apollo is getting ready to fight the Russian boxer, he comes out with white boxing gloves on. Sometime during the announcement of the fighters, the camera shows Rocky and Apollo standing in Apollo's corner. Apollo is jumping up and down while pointing with an ungloved and untaped hand, He is saying "I want you". The next time they show Apollo, he has his gloves on again. (00:26:55)
Plot hole: At the end of the film, we see Edward carving ice sculptures in his mansion. How did he get the ice up there? First of all, it takes place in a warm climate and I didn't see a freezer up there in the castle. He couldn't have gotten ice from town because firstly he had scissors for hands and couldn't have gripped the ice. And, even if by some miracle he could, he wouldn't be able to buy any from town because everyone in town but Kim was convinced that Edward was dead, she told everyone that they killed each other. And Kim didn't bring it to him because she told her granddaughter in the end that she never saw him again after that night. So where did he get that ice?
Continuity mistake: After he climbs out of the air duct, John McClane's shirt goes from white to green. The dirt and grime from the air duct would cause discolouration only where the shirt comes in contact with the duct. However, his shirt is uniformly green including places that wouldn't make contact and it is impossible for all surfaces to make contact even in small areas. (00:23:05 - 00:56:30)
Factual error: Jonathan is lying in the middle of the skating rink when the second cashmere glove falls upon him. Looking around, he notices Sarah at the edge of the rink. Despite Sarah being a female and the fact that it is snowing, even Nolan Ryan would have a difficult time throwing something as light as cashmere that distance. (01:22:05)