I'm curious about his electric vertical take off and landing supersonic airplane idea. He has mentioned it in several interviews so far.

I wonder how he plans to position the electric motors and the fans. Vertical take off needs a huge amount of power compared to normal runway take off, that means bigger batteries...

He surely has based the concept in first principles, but I must be missing something about this one.

Just speculating.. do you have to take the launch batteries with you?

That's what I was thinking. In my head I was seeing something still connected and that once it's actually airborne the craft jettisons the power cables.

Or maybe there's a way to fundamentally re-think how we're designing airports.

I didn't think it that way, maybe a vertical launching tower to give the initial take of acceleration with linear induction ala Hyperloop. It's a good idea.

Interesting hack. The video is interesting starting from the beginning, but the URL as submitted adds t=1849 which is the discussion about bitcoin.

More of a feature that a hack. If you click the share button there is a "start at" input.

My thought on the hack was submitting a BitCoin post to HN with the title Elon talks about Tesla and SpaceX :-)

My guess was that they paused after watching the part about SpaceX and Tesla, opened up share, cut and pasted the URL, not realizing that the video would start after the discussion and instead just be the part about Bitcoin and Paypal. Perhaps I am to easily amused.

It also works with #t=30m49s at the end of the url.

he doesn't seem to care about bitcoin. that's okay with me...

Was not expecting that low blow on bitcoin.