Corrected entry: When the Little's go looking for Stuart they leave the baby in the taxi.
Corrected entry: In one of the opening scenes, Stuart is sleeping on the top bunk, and George is in the bottom bunk. In a later scene, the night after the soccer game when Stuart and George are going to bed, there are no bunk beds. Stuart walks across to his own bed that is sitting on the floor, not on top of George's bottom bunk.
Correction: There are bunk beds. The top bunk bed was remodeled to where Stuart basically had his own bed, bedside table, coat hook and everything else. He practically had a mini room on the top bunk.
Corrected entry: Near the beginning of the film, Margolo pretends to have an injured wing and Stuart takes her in. The next day when Mrs. Little and Martha go for their stroll, Margolo flies onto the roof to strengthen her wing. This is all fine and dandy, but how can an injured vertebra be strong enough to place pressure on it the next day? Wouldn't Mrs. Little have suspected something fishy at the sight of this?
Correction: She was actually faking it. Falcon revealed that when Stuart confronted him.
Corrected entry: When Stuart first gets in his brother's plane and he flies outside and crashes in the park, the family runs to see if he is OK, but they forget the baby at home all by itself.
Correction: This isn't a movie mistake - it's a parenting mistake (a rather severe mistake), but character stupidity or errors by characters (unless they mess up the plot of the film) are not mistakes.
Corrected entry: If the Littles can hear Stuart and Margalo speak, how come they can't hear Snowbell?
Correction: Because Snowbell never speaks in front of the Littles.
He does talk in front of the Littles - at the end of the movie when Margalo says she'll miss him too he says "I'm not going to cry" but the Littles never reacted to him speaking.
Corrected entry: Why would the falcon want the ring? Even if he cashed it in for human money, how would that have value to a bird?
Correction: It's for the same reason humans have jewellery: owning valuable things makes one feel important.
Correction: Once again - another parenting/character mistake - not a movie mistake.