Audio problem: At Thomas J's memorial service, Vada goes up to the coffin crying. Just after she says something about his glasses being missing, her father comes up to comfort her. Watch his mouth - he is heard talking but his lips aren't moving at first (they are in the next shot).
Continuity mistake: In the scene where Thomas J. pulls the fish out of the water, the hook falls out of the fish's mouth twice.
Audio problem: When Vada and Thomas J are running away from the bees, Thomas J yells, "Run faster, they're after us", but his lips aren't moving. Neither does Vada's, when she replies, "I am running faster."
Continuity mistake: Vada loses the right handlebar streamer in the garage, but later in the movie it's the left streamer that is missing. At the very end we see that she has both streamers. (00:35:15 - 01:16:25)
Visible crew/equipment: When Thomas J. is leaving from his porch, after Vada tries sneaking him out of his house to go spy on her dad at the Bingo game, if you look down at Thomas J.'S shoes after he steps off the porch, the red tape mark is visible.
Factual error: The pirate ship ride was not invented until 1981; however, it appears at the carnival that is supposedly taking place in 1972.