Why are we so sure these UAP sightings are crafts originating from outside of our Earth?

There is no question that there are unidentified (possibly alien) crafts flying around in our airspace. But, why are we all so convinced that these crafts are from another planet or solar system?

I’m curious to understand the obsession with other planetary life being the explanation for this phenomenon. Playing a bit of devils advocate here.

Many times we see these crafts above the sea or coastal areas – sometimes they even enter and emerge from the oceans. Knowing that the vast majority of our oceans deepest areas have yet to be explored, is it out of the question that these beings are not actually extraterrestrial whatsoever and have been living in the depths of our seas undetected this entire time? Harvesting hydrogen and using it to propel their vehicles and support their underwater civilization?

Then comes the question of how these crafts enter our atmosphere undetected. I recently read an article about a 2ft long asteroid that entered our atmosphere traveling at a very high rate of speed. Scientist we’re all over this way ahead of time. The thing left a streak across the sky similar to a shooting star or a comet. No satellite imagery of UAP’s anywhere, but we can track a tiny rock plummeting towards earth? No photos of UAP’s on approach or way out there somewhere in space? Or signs in the sky of them entering our atmosphere? That seems strange given how many satellite based cameras we have watching earth and looking out from earth into space.

This still leaves potential for holographic universe theory or some sort of teleportation based mode of travel but I’m interested to start the conversation. Please leave some thoughts below!