At the airport this past summer, I overheard a young child ask his mother a wonderfully inquisitive question: "Why can't we just fly the plane into space? And then we can see the stars and the moon, right?" The Mother, to her credit, gave a correct although short answer: "Planes aren't built for that, honey."
A conventional jet plane can't go into space because one, it can't generate enough speed to enter a low-earth orbit. Two, it is not built for the riggers of the vacuum or near-vacuum of space. And three, its engines need the oxygen in the atmosphere to burn its fuel. Research for breaching space with a plane actually began in 1947 with Chuck Yeager and his X-1 plane, which first broke the sound barrier. This was the first of many "X" planes, both air jet and rocket, that have made very high-altitude flights reaching the fringes of space since the 1960's. "X," by the way, is what is used for any experimental plane.
Now when the soviets began putting objects in orbit using modified ballistic missiles, the U.S.A. had to keep up and switched away from planes to rockets. Today NASA and companies like Lockheed Martin and Boeing are hard at work creating the next generation space shuttle and space planes. On which you could take off from your local airport and go into space where you could stay perhaps at an orbiting space hotel or land on the other side of the earth after only a couple of hours. The current timeline makes space tourism possible for the average person in about 25-30 years. For more information about space planes, I encourage you to visit NASA.gov and HowStuffWorks.com.
Follow your curiosity to the Fred G. Dale Planetarium at Wayne State College.