A NASA astronaut and a Russian cosmonaut can't be creative. He has to follow a predetermined detailed checklist written by an engineer and if he gets a little creative he'll never fly again.

I spent about seven years during the Vietnam War flight-testing airplanes for the Air Force. And then I went in and I had a lot of fun building airplanes that people could build in their garages. And some 3,000 of those are flying. Of course, one of them is around-the-world Voyager.

The criticism is, once I get something flying, I lose interest in it.

I like to call the difference between research and development. Some people use that interchangeably. They'll say R&D. They're two totally different things.

Achieving something that has never existed in manned spaceflight and that is high volume and public access.

To allow public access to orbit, we would need breakthroughs that would lower the cost by a lot more than an order of magnitude and increase safety by a factor of 100 as compared to every launch system used since the first manned space flight. I think airborne launch will be a significant part of the safety solution.

We didn't have practical model rockets in the '50s. The ones we made were very dangerous and the kids that played with them didn't have all their fingers, and sometimes were blind in one eye.