With only 26 episodes, something went wrong in the top office, either it was too smart or somebody at Hanna Barbera didn't like all the gun action, and people actually got killed in this cartoon, they did not come back with only gun powder on their face.
As well as Race Bannon and his girlfriends, as if kids never seen such things in the 1960's,... but maybe not in cartoons. It was meant for 8-12 year olds? maybe to many 5 year olds watched, yeah, they might have learned something. Nothing they never seen before on TV, as if they didn't watch Westerns. The adventures of "Jonny Quest" was yanked after one season. 1964-1965.
Rumors are they may have went over budget. But did not realize just how good of a cartoon they had until 3 years later.
Whatever the reason, this show shoulda had a 4 year run. 90 to 100 episodes would have been great.
It still stands the test of time.