Revealing mistake: As Annie gets ready to call Sandy to go to the Warbucks house, you can see the right side of Sandy's head, as they wait for the cue to send him in.
Audio problem: Right after the girls find Sandy they start running again to Mr. Warbucks' house. One of the girls says that she can't run anymore but her mouth doesn't move.
Factual error: This film is supposed to be set in 1933, but at one point we see a helicopter, a machine that wouldn't be invented until after World War II.
Suggested correction: The helicopter was originally theorised by Leonardo da Vinci in the 1400s. Early practical versions began to appear in the 1920s, and by 1932, helicopters were able to carry more than one passenger. Although a machine that could carry three people from NY to D.C. was not possible in 1933, in the context of the movie, Warbucks would be able to afford a privately built copter, with improvements of course, for personal use.
Other mistake: The scene where Robin Ignico mentions Annie's new dog Sandy "but there's no bite in him," Lucy Stewart can be seen re-mouthing Robin's line.