Plot hole: When the aliens kidnap the adults, the kids are left behind. But all the kids seen are around 11 and younger. Where are the teenagers or young adults? None of them are during the celebration scene nor in the arena on the alien planet.
Plot hole: At the beginning of the movie, Jimmy's rocket could barely stay in one piece, much less leave the atmosphere. And that was only one rocket. But later on, not only can he build a much better rocket from one of the rides in the amusement park, but he can build ones for the other kids as well. It's not like he got better at building rockets, he tried to build another one in his yard before he and the town's kids did, but it fell apart.
Plot hole: Jimmy enacts a ploy to make Ooblar think Goddard will self-destruct in a massive explosion. Ooblar runs out of the lab where Goddard escapes and frees Jimmy and the kids from the dungeon. Shouldn't have Ooblar realised something was up when no explosion occurred and went back to see the dog and the kids have escaped and sounded the alarm, especially to King Goobot? Yet the Yolkians are shocked when they see the kids in the arena later, meaning Goobot was not informed about it prior by Ooblar.
Plot hole: When Jimmy is piloting the Yolkian cargo ship, while being chased by the Yolkian Armada, he steps on a pedal as he flies the ship around a star to escape the chasing ships. The vessel he is piloting was built and designed by a race of aliens who don't have solid bodies and use hovering pods to move around. There is no reason the ship should have pedals or pedals placed in any way that would require the pilot to have legs.
