I study UFOs from angle of science and technology, because I like learning about those two subjects anyway.
So when one listens to witnesses one actually comes across technologies that we have, but in a rudimentary form. For example, there were several stories about soldiers capturing ufo and than trying to enter into it by cutting open an entrance with a blow torch. These blow torches normally can cut the hardest steel as if it was butter and they can melt diamonds. Yet, these soldiers were unable to make even a dent with such blow-torch, for days on end.
Now, we actually know how to make such hard alloys. Its called nano-technology. But nano-tech materials can now be only made in a labs, by assembling them atom by atom. If you want, we understand theory, but engineering is not there yet.
Or another one. Bob Lazar described alien craft and in particular 'amplifiers'. Amplifier is a cylinder made of very heavy trans-uranic metal (heavier than depleted uranium), about 75cm (2ft) in diameter, and about 1.5m (4ft) long. Most likely it weighs at least 4-5 tons. Amplifier is attached to the hull with an unassuming hinge, so it can pivot in any direction. But pivot is not a ball in a socket, like we would do, for example on a camera tripod's head. Hinge was just a straight tube, surrounded by magnets. They would change magnetic field, and hinge tube would respond to that and twist. Something like that can only be done with nano-materials.
Or frequently mentioned beams that UFOs project. Beams like that were projected in front of major Holt's feet in Benwaters case. Beams like that were used to turn off nuclear missiles in Montana silos. In few cases, UFOs used such beams to inspect vehicles before they approached drivers. Etc. etc. Actually there is a next generation of radars which is currently under intense development in US and Russia. These next gen. radars will work on frequencies much higher than micro-waves, very close to infra-red and visible light. Such an radar will be able to project a beam at a plane that is 50miles away, scan pilot's face and check his name in a database of pilots. More than amazing, indeed. Now these next gen. radars, in a rudimentary way, sound like these beams that UFOs produce, because they work in visible light spectrum.
There are many such cases where there are our technologies that are just few antagonizing steps behind them. Colonel Corso actually said that the only area aliens are far in front of us is genetics. And what aliens spend most of time doing? Co;lecting biological samples!