Im only going to state the facts of what I saw one day while walking with my girlfriend down the street: I was looking up towards the sky in the general direction of N/NE , I was observing while walking, the commercial airplanes taking off from the airport which is probably about 40-50 km away.

So I observed an aircraft which looked to me like it was taking off and gaining altitude, and as I looked at this aircraft, behind it and to the right, next to the tail was a silver disc. I am not able to tell you in feet how far away this thing was but I would have to say at least within a 100 feet, enough that me looking on the ground was able to see a clear distance between the airplane and the silver round object.. I could not take a photo as when I looked again it was gone.

This lends me to believe it was an optical or otherwise illusion that was created from the plane and the cloud reflecting it? but im not sure, which is why im asking any aviation experts to reassure me that what I saw was simply a reflection of the plane in the sky, but what kinda makes me wonder is that:
It was a perfect looking circle of silver, or disc. Can anyone tell me anything? Ive been reading about this at length and even thought maybe I should not post this for fear or something. But I decided it was probably something I should ask just to reassure myself what I saw was not a UFO. Was it polarization?

Can people see reflections from planes in the sky on a partly cloudy but otherwise sunny day? Thanks

UFOs can be self illuminating.
As the theory goes the electrical/mechanical vibrations move the air
molecules into illumination by moving electron into and out of quantum
orbits or by hitting the hull of the ship. Guess who worked with these
types of electrical vibrations. So powerful the emanations from a X-Ray
type bulb of half sphere round gave off neutrinos in a focused K capture.
This is big time science.
ED: Yes there are ships no one talks about and people see them all the time
for many years now.

I have this sneaky feeling that you most likely witnessed an orb type UFO, like so many others have witnessed including myself. I've seen orbs on more than one occasion. Even after you've seen, it's hard to believe the eyes but they ARE real.

Our govt keeps more things hidden from us than the number of hairs I have on my head! is my opinion.