Large Grey disk approx., 100 feet in diameter was traveling sw to ne silently without lights.

I had stepped outside to smoke a cigarette at approximately 2:30 or 3:00 in the morning and while standing there looking at the stars, I witnessed a large, grey disk float by overhead. It was about 100 feet or so above the trees and was traveling from SW to NE and made absolutely NO noise and had NO lights showing. It appeared to be around 100 feet or more in diameter and was barely lit up from the city lights below it. It appeared as a ghost, grey disk and just silently moved across the sky until it was out of sight behind the trees.

Artistic depiction of flying saucer https://www.cgtrader.com/3d-models/space/spaceship/flying-saucer-sport-model

The lights were so bright I can only guess the shape.

I was giving my dog an extra walk and at 9pm there are usually several people around but I was the only one. I walked to the corner of the building to look into the darkness and the night sky as usual and there it was. It seemed close,,,not high up like the space station, it seemed to be as high as the small private planes that fly over sometimes. I stood still thinking it must be a plane and it only appeared hover or stand still,,it did not move. It appeared to be round but the 3 to 4 round lights were so bright. i thought maybe a helicopter but there was NO sound and I thought a hovering helicopter would be looking for someone and flash their beams around..no beam, just bright and silent. I waited what for about 15 min (it is hard for me to stand for very long and I went in the house) Sometimes it seemed to shift sideways a bit, or appear as though I was looking at it through the trees I was not.

Egg-shaped UFO over Maryland July 2016 http://www.latest-ufo-sightings.net/2016/08/solid-egg-shaped-ufo-photographed-maryland-16-jul-2016.html

Artistic depiction of flying saucer https://www.cgtrader.com/3d-models/space/spaceship/flying-saucer-sport-model

Large bright white disk flew quickly across my house in seconds silently
 
 Was flying my drone and getting ready to land when I saw a large bright white disk above the cloud tops.  I live near an airport so I am used to the usual characteristics of aircraft but this craft flew from one side of the sky to next in 5 seconds max and it was also silent. 

It had consistent white lighting across the body with no other distinguishable lights or features. It was comparable in size to the moon except it was flying fast and not stopping. I am currently a graduate student in mechanical engineering, and have specialized in the study of fluid mechanics.