Let's be clear here before I even start, I do believe that there are other life forms in this universe, the sheer amount of stars out there tell me that.
I've seen some pretty convincing stories of "interesting" craft being spotted, but it's worth noting that such sightings are 50/50 in terms of who is piloting them. It's common knowledge that governments experiment with aircraft, it's to be expected.
I'm going to put this simply, early sightings of the Northrop Grumman B-2 Spirit were mistaken for alien craft, so it's not out of bounds to think that recent sightings of "ufo's" are actually military projects. With the leaps and bounds in technology recently, I am led to belive that there might be some fairly abstract engineering going on with whatever the military is toying with nowadays. What this all means is, most of what people believe are ufo's are probably the black projects of today, and of those projects, very few will actually see the light of day in terms of public knowledge.
Scientists and engineers are already working on cracking some pretty insane shit, the problem is time and current technology. For instance, nuclear powered flight has been a recurring idea for a long time (we've even had a crack at it a few times), but in terms of what we think is possible now, it's ancient.
It's the time of anti-matter now, it might seem alien, and that's because it is, but we're already working on harnessing it. It might seem hard to believe, but it is possible to manufacture anti-matter particles right here on earth, but it requires a particle accelerator. The only problem is, you need a REALLY big one to create amounts that are useful for research and examination.
If only we had one...
