Why is it that we are not further along with 'space travel' despite over 60 years of steady effort? It's very simple! For interstellar travel we have dreams but no technology, while for interplanetary travel we have technology but no dreams!
The biggest problem is getting there, and this is a simple matter of scale. Sailing ships and diesel-powered vessels are a good way to travel Earth's oceans, but the technology is inadequate for distances 100-times greater to get us to the moon in a few days. We need chemical rockets for that. Similarly, another 100-fold step gets us to interplanetary space, and for that chemical rockets are inadequate. We need a completely different technology such as ion rockets powered by solar or nuclear energy. But the biggest step is interstellar space. There, the distance scale factor is over 100,000 times greater than interplanetary distances. We need a propulsion technology that similarly has as much in common with advanced ion engines as the canvas in sailing ships had compared to ion engines. You can forget about 'warp drives' because physicists do not understand what space (e.g. gravity) actually 'is' let alone how to artificially change its geometry. There is actually no physical evidence that it is even a quantum field!
Then there is the matter of destination. As I have pointed out in my previous Huffington Post blogs and in the book Interstellar Travel:An astronomer's guide, the cost of interstellar travel is so great we will have thoroughly explored our destination by remote sensing long before we even begin our first flight. For trillion-dollar missions, we will not travel to a star that we do not know IN ADVANCE has a planetary system. But not just any planetary system. To justify the economics and safety risks, it must have an Earth-sized planet in its habitable zone with an oxygen atmosphere, which means a biosphere - which means life! We will simply not make a hundred-year journey only to live under a dome and explore in spacesuits a barren rock with a crushing gravity. Also, we are starting to create a catalog of Earth-sized planets in habitable zones close-by our sun. You can forget all the popular destinations closer than 50 light years like Alpha Centauri, Barnards Star or Epsilon Eridani. And if you want to have an oxygen atmosphere, well we haven't found one of those yet even after looking at planets out to 100 light years or more. Our first interstellar journey will not be a cheap jaunt to Alpha Centauri, but a far more technically demanding expedition beyond 100 light years... or further.