Whilst governments still build stuff and people take an interest there will be UFO reports. Just take a look at the 'X' designations and see how many there are. Was the SR-71 'normal' for it's time? If you saw it today would you not think 'What the hell is that?' My brother once saw it at (as I understand it) one of its very limited UK appearences and it was still glowing orange/red on approach.
An AV enthusiast or pilot/crew might look at a B2 and see the general evolution involved, but what about joe average? I was stunned by it and I've been a spotter since I was knee high to the family dog.
I generally disregard anything that involves LGM or the various 'abduction' scenarios as complete tosh. Anything that's accompanied by half the worlds special forces and a fleet of helicopters is, er, not exactly discreet.
But in many cases I think there is a grain of truth at the core of many UFO sightings. I just don't happen to think that the truth is 'out there', it's far more likely to be sitting in a wildly expensive shed somewhere with boffins crawling all over it.