a silent, dark, rectangular flying object

At about 8:30pm, 9/25, I looked up into the sky and saw an object coming toward me and my family overhead. In a matter of about 2 seconds I discerned it was large, dark and rectangular, and it was swiftly gliding past, lengthwise. It was silent. It had a "belly" of a single line of lights running down its length that flashed on and off one-by-one in order -- I recall them being red, blue, green, and white. I called out to my family to look, as we were outside eating. But then just as soon as I saw it and called out, the object literally "snapped" out of vision and was gone from sight for about 2 more seconds. And then, as it was directly overhead, it snapped back on and was fully visible for 2 more seconds. At this point, one of my daughters also saw it. However, she was the only other one who saw it during that second phase of visibility because she was not under the sun umbrella we had left up (my husband and son had an obstructed view and didn't see any of it). And then it snapped back off and was completely gone.
Perspective is difficult to discern when something is in the sky, but my daughter and I had the first impression that it was huge. And about the distance up of about a small aircraft. I'd guess it was the width of my minivan and triple its length. It was clearly rectangular and dark gray, perhaps metallic. The lights were small, circular LED-like brightness. It was utterly silent. It "phased" into visibility, out of visibility, back into visibility, and then was completely gone in just a matter of no more than 6-8 seconds seconds. There were no clouds between us, though it was an overcast night.
I'd reached for my phone to record it, but I was only able to start recording after the object had already disappeared for good.