Other mistake: When the McCallister family is in the Chicago airport and Kevin is changing his batteries, on the P.A it says that American Airline flight 226 to New York is in the final boarding process, and Kevin runs after the man who is running to the gate. Once they are on the plane, the flight attendant announces, "Welcome aboard American Airlines flight 176 non stop service to New York." These are different flight numbers. (01:26:00 - 01:40:00)Etihad
Continuity mistake: At the end, Harry walks to the building's door, thinking he can get in. The bag with tools opens and tools fall all over him. After a few scenes, he gets up and you can see that the tools are in one place and not scattered anymore. Plus the bag and string have disappeared.
Continuity mistake: When Kevin is checking into the hotel you can see a pair of legs in the top right hand side of the screen. At one point they walk away and then are back in the very next shot to continue standing while Kevin talks to the hotel lady.
Factual error: When Harry and Marv arrive for the first time at Kevin's "funhouse", they look up to the roof and spot Kevin taking a Polaroid of them. The flash brightly illuminates them both, but the building looks to be at least 30 feet high; a basic Polaroid camera does not have a flash strong enough to reach such a distance (plus the street is already illuminated by lamps and Christmas lights). (01:23:05)DEvans
Other mistake: When the family arrives in Miami, they pass Kevin's bag until they reach an old man, dressed in shorts. In the initial airport scene, while Kevin is chasing his father, the same old man is there, dressed in a business suit.
Continuity mistake: When Harry goes up the steps leading to the back door of Kevin's uncle's house, the wooden planks he kicks away are in a different position to when he first enters the alley.
Revealing mistake: In the whole scene where Harry's head is caught on fire to the part where it shows the explosion outside the building, this is quite obvious that the whole scene was done during the day.
Continuity mistake: Kevin asks the limousine driver, "Do you know any good toy stores?" His glass of Coke is almost empty. When the driver says, "Yes sir.", it is three-quarters full.
Continuity mistake: When the vans from the airport arrive, notice the second van to arrive smashes the statue in front of the McCallister's door all over the pavement. When the whole family is running out of the house into the vans, the statue is standing perfectly again like it hadn't been touched at all, but pieces of the feet were broken off, so it couldn't have just been stood up again.
Continuity mistake: When Kevin is running from Harry and Marv he breaks a fake pearl necklace to spread the beads all over. You can see after he drops them all that they have spread far apart. In the next shot where Harry and Marv's feet are shown there are a lot more beads all together which is why they slipped on them.robsuttonjr
Continuity mistake: Kevin's mom goes to the 3rd floor to lecture Kevin. When Kevin stands they move shots between mom and Kevin who is standing still. There are 3 separate shots of Kevin in this sequence. In the 1st & 3rd shot his left collar button is covered and his hair bang is above left eyebrow. In the second shot the left collar button is visible & the hair bang is lower touching the left eyebrow.robsuttonjr
Revealing mistake: In the scene where Kevin runs into his relative's abandoned house in the middle of the night to set the traps, he runs down a ramp. You can tell that shot was filmed in broad daylight.
Continuity mistake: Before Harry jumps for the ladder, there are several close-ups and there is nothing on the bottom rung. When Harry jumps, the bottom rung is suddenly covered in green goo causing him to slip.
Continuity mistake: When Harry slips off the ladder outside, he falls backward towards the pallet on the ground (a few feet away from the ladder), but then suddenly the green slime falls from the ladder straight down onto his face. The slime would have landed on his feet or maybe legs, but by this time his face was well clear of the ladder.
Factual error: The AA flight number to Miami is a 4 digit number beginning with a 5. These are regional flight numbers but the family flew on a mainline 767.