A bright silver light appearing out of nowhere, then completely disappearing.

Traveling southbound on I-15 in Utah County, Utah, I suddenly noticed a bright silver light in the sky around 1:15 in the afternoon. Although there were some clouds in the sky here and there, the area where I saw this light was absolutely clear. The light was probably at a height equivalent to what we would expect from a small airplane’s typical flying altitude. This light then faded away completely. I carefully kept my eye on the area where I saw the light as I continued to travel on the freeway, moving closer to the location of the light. Then the light faded back up, literally out of nowhere, as there was nothing visible to the naked eye in the sky where it appeared. This fading in and out of existence happened probably 3 or 4 times and then it completely discontinued. I watched this area for some time, but was unable to see any kind of object in the sky whatsoever. The bright silver light I saw, when it reached its maximum size, appeared to me to be an actual object, something possibly the size of a small airplane. Because it was so bright, as far as its shape, I can only say that I think it may have been slightly elongated horizontally, but of this I’m not absolutely sure because I only tried to recall that detail from my memory after the fact.