to make a fuel effiicent car engine probably needs a mechanical engineering degree possibly at the doctorate levelto operate a bank needs a degree of finance, and to become a member of institute of bankersto operate in insurance company needs a degree in business and acuturial sciencenote however that the above degree only let you familiar iwth the the industry, and does not mean that you open your own company. opening a company needs lots of money from you and from your investors who trust your work ethics, expertise, hard work, etc. In other words, it is easier to say than done, not that i want to rain in your parade. how old are you anyway and are u the brightest student in your class and will likely go to the ivy league school someday on scholarship?
You should start out as an engineer in an existing car company to learn the business. You can choose a large vehicle manufacturer, or choose a smaller cutting edge company that builds experimental cars. You should aim to earn a degree in Mechanical Engineering. Business classes will help, but they are not necessary during your years as a staff engineer. You can acquire a great deal of information by learning from others and reading business literature.