For a change, I'm going to post the video first, and let the swank theme music get you in the right mood. The video was uploaded by TonyBeazley to YouTube:
Jonny Quest was the last primetime series Hanna-Barbera would produce for ABC until 1990's Capital Critters. The one common link between the two shows is that neither one lasted beyond one season.
While The Flintstones was still going strong, entering its 5th season, H-B couldn't keep anything else on the air as a complement. Top Cat & The Jetsons each lasted one season as well, and, like Quest, would find new life in Saturday reruns.
Unlike those others, Jonny Quest was a straight-up adventure series, a precursor, if you will, to H-B's entry into the superhero sweepstakes. Jonny (Tim Matheson) traveled the world with his father, scientist Benton Quest, their dog, Bandit, and bodyguard Roger "Race" Bannon, a former government operative. The episode, "Calcutta Adventure", explains how Hadji came to join the Quest team. I'll see if I can get a complete, uncut version of that episode one of these days.
In an effort to fill time on their Saturday schedule, CBS acquired Quest a few years later, and the series would resurface on NBC in November 1978, when the network overhauled its lineup two months into the season due to ratings issues. Series creator Doug Wildey was back at Hanna-Barbera by that time, overseeing The Godzilla Power Hour, which expanded to 90 minutes, becoming Godzilla Super 90 with the addition of the Quest reruns.
In 1985, Jonny returned with all new adventures as part of the Funtastic World of Hanna-Barbera syndicated anthology block, and that lasted about twice as long as the original series! Cartoon Network took a turn 11 years later with the daily Real Adventures of Jonny Quest, which added about 3-4 years to Jonny & Hadji, and added Race's daughter, Jessie, to the Quest team. Surprisingly, the writers couldn't find a way to link Jessie up with either of the boys to build a relationship.
But the original Quest can be best defined as a tough act to follow. None of the adventure series H-B would produce post-Quest could match it in artistic terms, and that's despite another noted artist, Alex Toth, being the designer for Space Ghost, Birdman, etc.. Currently, Boomerang has Quest airing nightly, but airing only the superior original series, which cycles through on a monthly basis. Hey, they won't listen to us mere mortals, otherwise they'd keep it weekly, the way it was originally, and the way it's meant to be.