There was no looking back after the wheel was invented. It allowed people to build carts to transport their goods and, eventually, those carts turned into means of transportation for people. But there were also horses, and donkeys, and bullocks for transporting goods and people. There were stagecoaches, and trains, and cars. And there were boats--all kinds of boats--and all kinds of airplanes. People are very good at inventing ways to make their lives...