"Dr. Foldes, how did you suddenly think of this?"
Martha Owen was very puzzled.
Dr. Foldes said solemnly, "You just mentioned driving."
"Yes."
"What do cars look like now?"
"There are no cars anymore, only single-person flying vehicles. The maximum flight distance of a civilian single-person flying vehicle is ten billion kilometers, which can approach a range of twenty million kilometers from the sun and can also enter gaseous planets."
Dr. Foldes gave a slight smirk, "But ancient cars weren't like this; they had four wheels."
"Traditional internal combustion engine cars, I know. What about them?"
