I, too, believe that there are UFOs. Indeed, it is a fact that there are UFOs....that is unidentified objects. But that does not mean that they are of extraterrestrial intelligent origin. The odds that they may be are miniscule. The interstellar distances are unimaginably huge. Voyager, which is now proceeding to interstellar space(it is in the Kuiper cloud belt which is the farthest object still associated with our solar system), is traveling at about 7km/sec. At that speed, it will take about 75,000 years for the spacecraft to reach the closest star system which is Alpha Centauri(about 4.3 light years distant from the solar system). In order to achieve meaningful interstellar travel, one must attain relativistic speeds, enough so that the travelers' proper time slows relative to earth bound denizens and distances shrink. However, there is a practical limit to the relativistic speed that can be achieved. At significant relativistic speeds, the spaceship encounters deadly electron and proton radiation that easily can penetrate any shield. The bigger the shield, the more fuel is required. Practically speaking, interstellar travel is highly unlikely except possibly for a type two or three civilisation. They would be unimaginably far advanced and would be Gods to us as we are to ants. They would have no reason to visit us assuming that they could find us as we are in a back-water in our galaxy, about 25,000 light years from the centre stationed on the tail of one of the spiral arms. However, it is possible that von Neumann type probes could possibly colonise the galaxy in a period of 10 million years or so. In all probability, these forms would not be carbon-based but rather silicon based(courtesy of Ray Kurzweil of the "Singularity").
The answer to Fermi's paradox---where are they?---is that they are there and not here and will probably stay there. It is easier to explore a virtually rendered universe unless we are already in one. The universe we inhabit with NWBO may just be one. As James Jeans once said.....the universe is queerer than we can imagine.
