Continuity mistake: When the house first becomes detaches from its foundation and becomes airborne, Russell is nowhere to be seen, although every angle of the house is shown, including underneath, the front porch and the back porch. He knocks on the door and tells Carl he chased a "snipe" under the porch - but he cannot be seen after liftoff and prior to knocking. The same thing happens near the end, when Dug claims to have hidden under the porch.
Continuity mistake: When Russel is complaining, when he says "Zoology" his face is covered in dirt. When Carl tells him that he can do his business in the bushes, he is instantly clean. http://www.youtube.com/watch?v=lOjhfcBNZW8.
Continuity mistake: When Mr Fredrickson opens the door there are 4 locks on the front door looking from the outside in. Next scene and consequent scenes there are only 3. (00:12:35)
Continuity mistake: When Carl returns to the house after Ellie dies and walks into the house, the mailbox is shown as being attached to the second fence slat from the post. All other scenes - both before and after this - show it attached to the first slat.
Continuity mistake: When Mr. Carl notices his mail he holds the stick in his left hand and reaches near the mailbox. He places the walking stick to his left, the next shot after he picks up the mail and comes back, the stick is not found, but in the next shot it's found to Mr. Carl's right side when he speaks to the man in black suit.
Continuity mistake: When Carl rids his house of everything and lifts off again to save Russel and Kevin, the camera pans down and one can see that the porch is empty, above and below. Afterward, when Dug knocks on the door, he said that he hid under the porch, which was empty.
Continuity mistake: When Russell lifts off from the roof of the house with Carl's leaf blower, it is obviously gasoline-powered because he pulls the starter rope and we see smoke. Once inside the blimp, Russell uses the blower on the bulldog and he starts it without pulling the rope.
Continuity mistake: When Ellie first shows Carl her Adventure Book, page 1 is a map of South America, page 2 is the library-book picture of the falls, and page 3 is the page marked Stuff I'm Going to Do. In the next shot, we see five pages precede the Stuff I'm Going to Do page.
Continuity mistake: When the house first lifts off, the bottom step of the front porch becomes detached at one end and sags. In the next shot when the house brushes the top of the transport van, the step is undamaged and isn't sagging.
Continuity mistake: After being tied up and rescued by Carl, Russell falls backwards off the front porch and is saved by the garden hose. In the first shot, Russell is standing on the nozzle hanging on, but when he is dragged across the windshield of the blimp, he is hanging on with his hands. The next shot in which we see him, he is back in a standing position. (01:19:20 - 01:19:50)
Continuity mistake: When Carl retrieves his mail (holding it in his right hand), he notices the dust and drops the mail on the ground to pick up the leaf blower. After using the blower and then the bullhorn, the mail suddenly appears back in his left hand.
Continuity mistake: The fence gate on Carl's house has some continuity issues. When we see him arriving home after Ellie's funeral, the gate is open toward the inside. The width of the opening looks to be fairly large, around 46 inches based on the total approximate widths of the planks on the house porch which is shown the same width as the gate opening (10 planks at least 4 inches wide and one plank at least 6 inches wide). The next day when Carl gets the mail, the gate opens toward the street and stops at the post - can't be opened to the inside. When the construction worker finishes his interaction with Carl, we see the complete gate and it is much narrower than the funeral shot. It now has only 4 planks which look about 6 or 8 inches wide, so the width is about a foot less than the night before.
Continuity mistake: After Muntz ties Russell to the chair and opens the ramp, there is a fast sweeping exterior shot of the blimp's underside from front to rear, and the ramp is opening toward the front. In all other scenes of the ramp, it opens toward the rear.
Continuity mistake: The angles of the sun in relation to the house in various scenes show that if looking at the house from the street, you are facing west. However, when the workers and Carl say "Good morning", the sun is coming from an angle which would indicate it's now late afternoon (not morning) because it's behind the house off to the left.
Continuity mistake: When Russell is trying to mount the camping tend for the night, one of the stakes bounces on his face, giving him a bruise on the left eye, but in the next scene the bruise is gone.
Continuity mistake: In the scene were Russell finds the lever to operate the house direction, he moves it first towards right, then to its left and again to its right and finally leaves it in the center and goes towards the window. But in the next shot, it's found positioning to its right.
Chosen answer: Carl and Ellie have two dramatically different personalities. Carl is more conservative, more reserved, a tender heart covered by a tough exterior which Ellie is able to break through, but which seems to recalcify after she dies. Ellie, on the other hand, is the sweet free spirit, rambunctious and adventurous. Throughout the film, each one conforms to the other until they ultimately blend into one beautiful unit. I think the makers of the film were trying to show that their respective personalities were a product of their upbringing, and reflected in the reactions of their families - hers larger, more fun, and more "hick" (we hear gunshots, for Pete's sake), and his more reserved, formal and patrician.
Michael Albert