I think that's the single best piece of advice: constantly think about how you could be doing things better and questioning yourself.

It is a mistake to hire huge numbers of people to get a complicated job done. Numbers will never compensate for talent in getting the right answer (two people who don't know something are no better than one), will tend to slow down progress, and will make the task incredibly expensive.

I think Tesla will most likely develop its own autopilot system for the car, as I think it should be camera-based, not Lidar-based. However, it is also possible that we do something jointly with Google.

It's OK to have your eggs in one basket as long as you control what happens to that basket.

Every mode of transport that we use - whether it's planes, trains, automobiles, bikes, horses - is reusable, but not rockets. So we must solve this problem in order to become a space-faring civilization.

I would like to fly in space. Absolutely. That would be cool. I used to just do personally risky things, but now I've got kids and responsibilities, so I can't be my own test pilot. That wouldn't be a good idea. But I definitely want to fly as soon as it's a sensible thing to do.

The rumours of the demise of the U.S. manufacturing industry are greatly exaggerated.