There are a few Dragon Ball Z scenes in which Androids 16, 17 and 18 ride a truck despite the fact that they are capable of flight. It grants extra time to the heroes to recover (such as in Goku's case) and think about or prepare for what to do next, like exploring Cell's egg, or merging Picollo with Kami. To me, it seems both unreasonable and humorous at the same time.
Nevertheless, I don't understand the reason for why the producers/storywriters decided to do this. Is there any reason given for this strange choice? Could it be some kind of plot hole or plot device?