Here's a local schedule grid and synopsis for the premiere episode. The "tonight" in the grid is Friday, Sept. 18, 1964, and the times are Eastern.

Notice that Jonny Quest followed an episode of Huckleberry Hound, which had been out of production for almost 3 years at the time. This might make you wonder if Jonny Quest was actually a prime time show, because prime time begins at 8 p.m. Eastern nowadays. In the early '60s, weekday "prime time" began a half hour earlier, which was after the evening news ended for NBC and CBS. It looks like ABC marked the 7 p.m. slot for local programming, like Huckleberry Hound reruns.