Some people need to quantify everything in finite, concrete terms that we understand. We think we know everything there is to know about our universe - that it's all been satisfactorily explained by science and Scientists. Thus, it *had* to be an RC model or some such. Anything else is just too incredible to comprehend. It is dismissed out of hand without further consideration. Can't be!
We humans believe in three dimensions: height; length; and width. The speed of light is absolute. Concrete. Measurable. Finite. And here on earth, those things apply (well, at least until you get down to the sub-atomic level, then all bets are off).
We know that inter-galactic space travel...at least with the means of propulsion currently at our disposal...is impossible. We can't even escape our own solar system at this point.
But what if there are dimensions of which we're not yet aware - dimensions that we cannot even imagine? (Like, how a dog has the ability to sense things that we cannot.) What if there are methods of propulsion and travel that we have not discovered?
Me, I don't rule anything out. *Must* the explanation of what the police pilots saw be of earthly origin? Certainly not! Could it have been..."something"...of which we have no knowlege, do not understand and cannot explain? Of course.
Does this bother me? Will I go out of my way to "conclude" that it must have been party balloons or RC models or just some sort of mistake on the part of the crew just so my brain won't short-circuit? Nope. Some things in life just have no explanation. Yet. In the meantime, I won't ridicule or deride any theory.