By 1931, after a few years' experience of flying scheduled airlines, those planes were operating at roughly 600 times the safety of the space shuttle. I look at safety not in terms of fatalities per passenger-mile, but when you get in and close the door, what is the risk of dying on this flight?

Within 25 years, virtual reality meetings will be essentially transparent to being there in person. Once we can do this, the idea of climbing into an aircraft, and burning up huge quantities of fossil fuels to propel our bodies and briefcases full of papers, will seem absolutely backward.

By 1931, after a few years' experience of flying scheduled airlines, those planes were operating at roughly 600 times the safety of the space shuttle. I look at safety not in terms of fatalities per passenger-mile, but when you get in and close the door, what is the risk of dying on this flight?

With any luck, by the time NASA's space probe hits Pluto, you'll be booking a spaceflight with a privately run suborbital airline.

We need affordable space travel to inspire our youth, to let them know that they can experience their dreams, can set significant goals and be in a position to lead all of us to future progress in exploration, discovery and fun. Thanks to the X Prize for the inspiration.

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 Russians did much bigger space launch vehicles for launching satellites and for getting men in orbit. They did that much sooner than America because America was very good at something else.