The rear door of the cab has Jet Line Cab Company over the medallion number. But in real life, all New York City yellow cabs have the words, "N.Y.C. TAXI" on the rear door over the medallion number.
At the beginning of the movie when the parents are putting the children to bed, the window at the end of the hallway shows that it is still daytime.
When Rocks begins to fight with the wolf, it shows that it's a completely different dog actor fighting the wolf.
When the cab skids off the road and down the hill you can see that it never actually hits the tree. It is yanked back before it hits it.
When Mollie yells Mikey's name at the airport when Mikey is on the luggage claim, Mollie's mouth doesn't move.
When Mikey says, "Mom, we need a dog."