O.K., let's forget about all the little inaccuracies of the series, from clouds on the moon or the fact that Commando Cody always escapes from the deadly peril in a scene we didn't see in the last episode's cliffhanger.
Let's remember that fabulous flying rocket suit, which spurred the imaginations of both scientists at Bell Labs who tried to recreate it, to the imitators, such as the graphic novel turned movie, "The Rocketeer" or several episodes of "Star Trek:Voyager" spoofing the classic Republic serials.
Add to it the incredible work of brothers Howard and Theodore Lydecker, whose expert flying rigs made all the amazing flights so realistic (I dare you to find the wires attached to the models!). Their work became the industry standard long before computerized digital effects. They were responsible for the smooth flights of fancy by famous fantasy crafts such as the Flying Sub in "Voyage To The Bottom Of The Sea", the Proteus in "Fantastic Voyage" and the Jupiter II in "Lost In Space" (Look to the third episode of the series, where the Jupiter II crash lands on the first alien world, as the saucer emerges from the fog over a ridge. Irwin Allen knew he had a winning effect, so to save money (He was Mister Cheap), he shot it in color, to be used again two seasons later when the series upgraded from B&W).