"Would you like to have your boss's job?"
Unless you have a better answer, the best answer for this question is a yes. However, you should clearly state that you want to learn everything and eventually move into a similar position. Do not sound like you are a person who is going to steal the job, but rather someone who is going to work hard to earn the position.
Short Answers
"When I gain a little more experience, I'll be looking to find a position that is similar to my managers job. But for now, I want to continue to learn as an employee while helping the company grow."
"I'm always learning new things and in time, I would like to have my boss's position. I believe I'm on track to become a manager and I'll continue to work hard to prove my abilities to the company."
"Yes. I have several years of experience and I also took on projects to learn more about management. I don't necessarily want to replace my manager, but I would like to learn more about management so I can be ready when a position is available."
Long Answer
"I would definitely like to have my boss's job. However, before taking on that role, I want to gain more experience and learn from my manager. I believe in thorough preparation and I am doing everything I can to learn more about management and taking on more difficult projects. I know through my hard work I will eventually have the opportunity to have a similar position to my boss."
Being ambitious is important and this answer shows that. It also shows that this person has a strong understanding on the steps to become a manager by learning about management and taking on more responsibilities. Finally the last sentence displays confidence. If you are creating your own answer, make sure use a similar structure as this one or if not, make sure it is better.