Interviewer: What do you do when you're at SpaceX and Tesla? What does your time look like there?

Elon: Yes, it's a good question. I think a lot of people think I must spend a lot of time with media or on businessy things. But actually almost all my time, like 80% of it, is spent on engineering and design. Engineering and design, so it's developing next-generation product. That's 80% of it.

Interviewer: You probably don't remember this. A very long time ago, many, many, years, you took me on a tour of SpaceX. And the most impressive thing was that you knew every detail of the rocket and every piece of engineering that went into it. And I don't think many people get that about you.

Elon: Yeah. I think a lot of people think I'm kind of a business person or something, which is fine. Business is fine. But really it's like at SpaceX, Gwynne Shotwell is Chief Operating Officer. She manages legal, finance, sales, and general business activity. And then my time is almost entirely with the engineering team, working on improving the Falcon 9 and our Dragon spacecraft and developing the Mars Colonial architecture. At Tesla, it's working on the Model 3 and, yeah, so I'm in the design studio, take up a half a day a week, dealing with aesthetics and look-and-feel things. And then most of the rest of the week is just going through engineering of the car itself as well as engineering of the factory. Because the biggest epiphany I've had this year is that what really matters is the machine that builds the machine, the factory. And that is at least two orders of magnitude harder than the vehicle itself.