As for the leather, we use tree bark. Oak trees mostly. Or at least I do. There's another process that uses a metal called chromium, which might actually be the kind of future leather you're thinking of, but I've never got a chance to experiment with it.
It's something I found out about while I was in the 31st century, and by that time they really don't like using animal products.
[Not that Hiccup could exactly blame them, after learning about what exactly had led to that. It still meant his experience with future leather tanning techniques was somewhat lacking.]
Re: locked, video
As for the leather, we use tree bark. Oak trees mostly. Or at least I do. There's another process that uses a metal called chromium, which might actually be the kind of future leather you're thinking of, but I've never got a chance to experiment with it.
It's something I found out about while I was in the 31st century, and by that time they really don't like using animal products.
[Not that Hiccup could exactly blame them, after learning about what exactly had led to that. It still meant his experience with future leather tanning techniques was somewhat lacking.]