Depending on the Artist (Toei Animation): Toei has worked on the 3rd season but only 2 episodes was done in house at Toei when the rest of them were outsourced to other studios, here is a list of the subcontracters Toei used on The Jetsons note Toei also worked on 2 episodes for season 2 Elroy in Wonderland and The Vacation, both are shipped off to Dai Won and both are uncredited on both fronts.
Keep Circulating the Tapes: After Warner Bros. released the 1960s episodes on DVD, it took another five years for them to start releasing the '80s seasons on that format, and yet another five years for them to complete that era. Additionally, the latter 2/3 of the revival, including the TV specials The Jetsons Meet the Flintstones and Rockin' with Judy Jetson, became available only through the Warner Archive.
The Danza: Besides George O'Hanlon as George Jetson, D.J. Rick Dees has a small role as "Rocket Rick", who is also a D.J.
Executive Meddling: Janet Waldo had already recorded her lines as Judy Jetson only to get bounced from the movie in favor of late 1980s pop star Tiffany. Waldo has said she found out shortly after the decision was made, and it was highly publicized. She was pretty upset at first, but has admitted it's become a non-issue, and doesn't hold any ill-will against anybody, not even Tiffany. On the other hand, George O'Hanlon and Mel Blanc were beyond pissed off about the Stunt Casting, and demanded that Waldo be reinstated, to no avail. It didn't even work out for the studio. Animation Lead Time meant that while Tiffany was huge when they cast her, her fifteen minutes of fame were pretty much over by the time the film actually came out, causing the film to be a box office bomb.
Franchise Killer: Coming on the heels of the 1980s Jetsons revival (the new syndicated episodes and two TV movies), this film's disappointing box office and harsh critical reviews were apparently enough to send the franchise back into hibernation. It has stayed there ever since, a potential live-action film being stuck in Development Hell for years notwithstanding.
Elroy in the movie grows up to become REVOLVER OCELOT! Seriously, that's Patric Zimmerman giving the voice.
Brad Garrett (in his film debut) voices one of the Jetsons' neighbors.
If you're a Mystery Science Theater 3000 fan, chances are you might recognize Cosmic Cosmo's voice as the same singer that Mike and the Bots mercilessly mocked during the end credits of Space Mutiny for the fact that the song he was singing was so blatantly 80's.
The Other Darrin: Pretty much everybody except Jane. Daws Butler (Elroy) died a year before the movie started production, so he was replaced by Patric Zimmerman. Mel Blanc (Mr Spacely) and George O'Hanlon (George) died during production, so the few unrecorded lines they had left were done by Jeff Bergman. And most infamously, Tiffany replacing Janet Waldo (Judy) after the latter had already recorded all her lines for the film.
The Mexican Spanish dub of the 80s series got it worse in the film: Not only the entire Mexican cast was replaced, the whole movie was dubbed in a Spanish-speaking studio in Los Angeles, CA, with an awful reception in Latin America.
Basically, almost every foreign dub has changed voice actors between the 60s, 80s and movie versions, mainly due to the time gap between them.
Stunt Casting: The aforementioned example of '80s pop starlet Tiffany as Judy Jetson. As mentioned above, it didn't quite work out.