Think about the military angle:
When I was much younger, a group of friends and I saw a UFO at dusk. It was the real deal - flying saucer and all. Absolutely blew us away. We weren't the only ones to see it, either: there were reports in the local news for several days of people seeing things at dusk.
Fast forward a few years, and there was our "UFO" in Popular Mechanics: a vertical take-off design tested and abandoned by the Air Force.
Oh, and yes, we lived only a few miles from an active Air Force base.
It was amazing how many triangular UFO's were seen in the 80's; how many of them do you think were 'stealth' fighter tests?
If you want to believe in UFO's, you are going to have to solve some very difficult engineering and physics issues. Relativistic space flight is a pretty big hurdle to overcome.