There was a blatant example of Bad Astronomy in Jimmy Neutron - the part where he along with all the other kids decide to build a fleet of ships to rescue their abducted parents, using fairground rides.
Now, ignoring the fact that the use of ferris wheel or roller coaster technology in space flight is controversial at the very least to most mainstream scientists, none of the vessels had a pressurised environment! All the kids crossed half the galaxy in open cockpits, their fragile flesh exposed to the vacuum of space. How did they breathe?
Not to mention the harmful effects of cosmic rays - none of the vessels seemed to have any adequate radiation shielding beyond limited alpha and beta particle resistance incidental to the metallic shell of the roller coaster cars used.
I had found this film to be very believable up until this point, but this blatant display of scientific inaccuracy totally ruined it for me from this point on...