It worked out flying though, millions of years before we did and we still don't do it as well. We can't even do walking as well as nature did.

Walking is easy compared to elbows, fingers and thumbs. It’s just falling over in a controlled fashion. I hear at least one company in Boston figured it out.

Anyway, humanoid robots should be big in the next 10-20 years. The compute, the batteries, the algorithms are all coming together.

We do flying better. If you adjust for our body weight, a modern airliner uses less energy per traveller mile than your average migratory bird. And the airliner goes much faster.