Stationary silver metallic oval object at high altitude during 2021 Houston Air Show

While photographing acrobatic and performing airplanes at the Wings Over Houston Airshow at Ellington Air Force Base on Saturday October 9, I noticed a single small metallic object at a much higher altitude than the performing aircraft and located directly overhead and slightly to the left.  Most of the performing aircraft seemed to be at altitudes between 300 feet to approximately 1,000 feet. This object seemed to be around 10,000 to 15,000 feet.  The object left no trail of any kind. I pointed the object out to my son and two other spectators one row over also began looking at it.  I observed the object for about 4 to 5 minutes. The object was too far away to make out details, however it was clear it was not an airplane as it seemed to be completely stationary in the sky. It was mostly a clear and sunny day and the object seemed to be metallic (silver) as I could see the reflection of the sun from it.  The object seemed round or oval shaped.  After a few m! inutes of being stationary, the object seemed to slowly drift to a different point in the sky and then again became stationary. I took a photograph of the metallic object with my Cannon EOS Rebel T6 digital camera with a 75-300mm zoom lens. I had to sit down in my spectator chair and point the camera directly overhead and slightly to my left to capture the object.  The object then slowly moved behind some clouds and I lost sight of it. Once we downloaded the digital picture and further zoomed in on our computer, you could make out a metallic oval shaped object.
I am 56 years old and am an Environmental, Health, and Safety Manger. I enjoy photographing wildlife and vintage aircraft at air shows.