Continuity mistake: When the Iron Giant follows Hogarth home they cross a railwayline and the Giant starts to eat the steel rail. During this scene you can see the distance of the railway sleepers changing from a fair distance apart to close together over the course of the shots. In the same scene you can also see that, although there is a crossing with lights, no vehicle could possibly pass as the rail has no crossover facility at that level. (00:24:30)
The Iron Giant (1999)
Ending / spoiler
Directed by: Brad Bird
Starring: Jennifer Aniston, Vin Diesel, Harry Connick Jr., James Gammon
Once the nuclear missile is launched, the Iron Giant sacrifices himself to save the town of Rockwell, Maine by flying into space and colliding with it before it reenters Earth's atmosphere.After his presumed death, a statue is built in his honor. Hogarth is now friends with the kids that bullied him; Dean and Annie are now a couple (married?). Hogarth discovers a stray bolt from the giant's remains, but it reactivates and makes its way (along with all the giant's other parts) to a glacier in Iceland, where he is self-reassembling.
CC
More mistakes in The Iron Giant
Kent Mansley: Launch the missile now.
Trivia: After Mansley's car is eaten by the Giant and disappears, Mansley is trying to get Marv to look at it but doesn't realise it's gone yet. Marv then asks, "What are we looking at here, Manly?" leaving out the S in Mansley to call him Manly. This was a mistake on the voice actor's part, but Brad Bird liked it and thought it appropriate for the character, so left that take in.
Answer: Turn back to/from what? Can you please expand on the question so we know what you're referring to?