Bright flickering sphere without sound stays in position for almost 5 minutes.

A bright flash caught my eye so i looked up and saw it.  It faded in and out of brightness a few times.  It was not a blink, or a timed fading.  More like it flickered in stages from light to dark.  It did not change position until the last flash of light that was shorter than the others.  There was no sound.  There was light cloud cover, and this object was below that, so i would have heard if it was a helicopter because it appeared about half a mile above me.  As soon as it vanished there were three planes in row heading west, and a helicopter moving back and forth north to south.  All of which I could hear.