Whats in the future for man and the automobile?

What happens next, when oil is depleted from the earth and there is no gasoline for autmobiles? this may not happen in our lifetime, but what does the future hold for our childrens children children? will “air cars” be developed for travel above ground, like the Jetsons? is the government making future plans for human travel, if this occurs? this may sound like a fantasy to you and i today, but this may be future reality more than we think. i can just visualize the interstates piled high with useless automobiles, because of no fuel. Question: what happens next, when oil supplies are depleted from the earth and there is no gasoline for automobiles?