Let's say these are ET drones. If they have to fly from Alfa Centauri, the closest star, which is at ~ 4.4 ly. If they fly at 0.99 c, due to lorentz shortening the elapsed time for the ship will be ~5 days. Hardly a problem if a spacecraft with the already displayed capabilities (accelerarion, as inferred from the Nimitz data) exists.
Calling them "already displayed capabilities" is a huge stretch. I've already posted a video showing that the "go fast" Nimitz video is probably something moving at about the same speed as a bird, or possibly a balloon at wind speed. There is no
real indication out there that these capabilities exist.
Also, I'm not sure where you get 5 days from. From what I'm seeing it would be more like ~230 days. Now that's not a lot, but that's from the closest star, and assuming that it is moving at 0.99c almost instantly. Which means we're already talking sci-fi technology here. It would take massive amounts of energy to accelerate something with mass to 0.99c. And in the end it all comes back to the same question. If any intelligence actually had both the capability to get here
and the will to observe us for (at least) seven decades, it's almost unimaginable that they would be this easy to spot. And somehow 95% of them are spotted in otherwise remote areas of the US.
Now the Chilean military
did spot one a few years ago, I believe. They concluded that it was impossible to explain, but in a matter of days it was proven beyond any doubt by randos on the internet that it was actually just a plane. So let's not assume just because someone flies a jet for a living that they're in any way qualified to conclude that the
most likely case is alien observation drones.
Edit: according to the calculator I used, to make it in 5 days they would have to be moving at something like 99.9995% the speed of light, which is needless to say many orders of magnitude more difficult than "just" 99%.