Betty Rubble was voiced by Bea Benaderet (1960-1964) and Gerry Johnson (1964-1966). Benaderet is also known for playing Gertrude Gearshift, Kate Bradley, and Pearl Bodine. Johnson was better known for theatrical roles in the Dallas Theater Center.
Old Shame: The Flintstones cast promoted Winston cigarettes during the show's first two seasons. Amusingly, those ads are now among the only vintage tobacco commercials that one can easily find online (since showing them is technically illegal just about everywhere on earth).
The Other Darrin: Hanna-Barbera voice actor Daws Butler replaced Mel Blanc as Barney Rubble for a few episodes in 1961 while Blanc was hospitalized after a near-fatal car accident. Hanna-Barbera, however, did not publicly acknowledge this, and Blanc was still listed in the closing credits.
Post-show examples. At this point, all of the original Flintstones actors, except for John Stephenson, have died and been replaced (some multiple times).
Gerry Johnson replaced Bea Benaderet as Betty Rubble in the show's fifth and sixth seasons, when Benaderet left to concentrate on her role as Kate Bradley on Petticoat Junction. Johnson died soon after The Flintstones ended its ABC run and would be replaced in 1971 by Gay Hartwig (Benaderet herself died in 1968, during Petticoat's run). Hartwig herself would be replaced by Betty Jean Ward, who was replaced by current voice Grey DeLisle.
Alan Reed lent his voice to Fred for the final time in the debut episode of Scooby's All-Star Laff-A-Lympics in 1977. He died soon after and would be replaced by Henry Corden. Corden died in 2005 and was replaced by James Arnold Taylor.
Aside from the aforementioned period of recuperating from his car wreck, Mel Blanc voiced Barney up to his death in 1989. Since then, Barney has been played variously by Frank Welker and Jeff Bergman (and Seth MacFarlane in parodies).
Jean Vander Pyl was the longest-surviving female member of the principal cast, playing Wilma until her death in 1999. Since then, Wilma has been played by Tress MacNeille.
The 2nd movie recasts all the characters due to taking place before Fred and Barney were married to Wilma and Betty
Recycled Script: There have been numerous episodes where Fred had a doppelgänger and in a TV movie from the 1970s, Fred took Santa's place. He did the same thing in the original show.
Recycled Soundtrack: In a sense. Mel Blanc's previously-recorded yaps for Dino from the original series were re-used for the films. Blanc himself had been dead for five years by the time the first film was released, and his voice was initially used without a screen credit, prompting his estate to slap the studio with a lawsuit before one was put in for the home video release.
The script for the first episode had Fred saying "yahoo". Alan Reed didn't like it, and asked whether he could change it to "Yabba-dabba-doo".
Barney's Vocal Evolution came about when Mel Blanc suffered brain damage in a car accident. When he came back to work, he suddenly started using that deeper voice for Barney (which was also a much closer imitation of Art Carney's voice - even though Blanc had originally refused to ape Carney) and no one said anything.
At one point, Richard Donner was attached to direct, Joel Silver was going to produce and Jim Belushi was going to play Fred. When the movie went from Warner Bros. to Universal, Donner stayed around but had to pull out due to conflicting schedules with Maverick.
Bill Murray, Dan Aykroyd, and Chevy Chase were all considered for the role of Fred, but they were all deemed too skinny, and putting any of them in a fat suit would look too inappropriate.
Moranis claims in an interview that John Candy was taking the role of Fred originally, but his death before filming ended up placing Goodman in the role at the last minute.
Which would mean that the movie was filmed and released over the course of little less than 3 months. Hollywood moves fast, apparently.
The role of Sharon Stone was written for... Sharon Stone. But due to scheduling conflicts with The Specialist, she dropped out and Halle Berry signed on.