From Radio-Info site, Braves2005 commented on that post:

I have a question about The Flintstones. Why did reruns of The Flintstones air on Saturday mornings on NBC starting in January 1967 and ending in September 1970 while reruns began in the fall of 1966 in syndication?? Were there any differences between the Saturday morning reruns and the reruns in syndication?? Also did ABC plan to air reruns of The Flintstones beforehand on Saturday mornings??

And Markd answered:

Actually I was led to believe Flintstones were not in syndication until the Fall of 1967 but I could be wrong. I know by 67 they were in reruns. Many TV stations ran them between 6 and 8 Pm initially much like stations run Simpsons & King Of The Hill Today. I see in old listings in the very early 70's that 5 WNEW TV New York ran The Flintstones mixed in with the sitcoms between 5 and 7 PM. By 1972 it was added to the morning kids block. For a while in the 70's and very early 80's 5 ran the Flintstones as a transitional show out of the afternoon cartoons and evening sitcoms much like they handled Bewitched, Gilligan's Island, Brady Bunch, and to a lesser extent What's Happening (which was percieved to be a kids sitcom by some).

Rights to the Flintstones changed hands and methods a few times. Hanna Barbara indeed produced the show but for Columbia/Screen Gems. Columbia would retain the syndication rights for the show. In 1965 they sold the show on a cash basis to the highest bidder. The show landed on independents in markets with one in most cases and in other markets a network affiliate.

In the 70's as independents signed on The Flintstones would change stations in such markets. In 1982 Screen Gems/Columbia sold the rights to all many of their older shows like The Flintstones (along with bewitched, jeannie, and Partridge Family) to General Mills. General Mills had a syndication unit called DFS The Program Exchange.

General Mills would distribute all their shows including The Flintstones on a Barter basis with no cash. Stations getting THe Flintstones would then agree to run 2 minutes of general Mills ads during The Flintstones and another 5 minutes spread out the rest of the day. Similar arrangements were made for other shows DFS distributed.

DFS would acquire shows like Bullwinkle, Woody Woodpecker, Garfield, Dennis Cartoons, happy Days, laverne & Shirley, Brady Bunch, Mork & Mindy, family Ties.
In 1991 Turner/Warner Brothers (which alos now owned the Hanna Barbara cartoons) bought back the rights to The Fintstones along with Scooby Doo. They then continued distribution but on a regular barter basis with Toy and Food ads already insterted in. They would run edited prints of the Flintstones in syndication while airing uncut prints on Cartoon Network.

In September 1997 Warner Brothers pulled all their cartoons from syndication including Scooby Doo, Flintstones, Smurfs, Yogi & Friends, Jetsons, and many others. They also pulled film shorts from Bugs, Porky, Tom & Jerry, Daffy and others from syndication. In 1998 Bugs & Tweety was pulled from ABC. From Fall 1997 to the SUmmer of 1998 WTBS 17 Atlanta was the last broadcast station left running the Cartoons. Then in 1998 WTBS ended the kids blocks as well.

From 1998-2002 Flintstones only aired on Cartoon network. From 2002-2003 The Flintstones aired on both cartoon Network & Boomerang. Today Flintstones only airs on Boomerang. I miss the days it aired on over the air TV.

I remember growing up in New Jersey when Channel 5 reran The Flintstones in the late afternoon-early evening. At one point, there were two episodes on weeknights and also Sunday mornings after Wonderama. It's a shame local stations don't carry The Flintstones. It was a major off network syndication success that made more money than the original ABC run.