It's also quite possible that our own assumptions that "we have the best military tech" may be a bit of hubris on our part...and other nations may have actually invested in something that can outmaneuver what we've got without highly publicizing it.
The "aliens from space" narratives tend to be non-compelling to me since it always seems based on the almost "sci-fi" kind of premise that all of the hypothetical aliens have modalities that are the same as ours, just more advanced.
When you think about it...In all of the planets and in all of the galaxies, if there was another intelligent lifeform out there that had the ability to reach our planet, what are the odds that they'd have, what's basically, just a slightly beefed up version of our tech? I would think that with nearly infinite numbers of combinations and possibilities, the odds of having that extraordinarily high level of similarity would be slim and none.