Bright white/silver rectangular object, no visible wings, moving E/NE in south central Louisiana.

We are a wife (me) and a husband in our 50’s. I’m a housewife; he’s an auto technician.
 I saw a very large white/silver rectangular object moving toward E/NE.  No wings, no lights flashing or otherwise but the object was very bright (the sun was still out and the sky was totally clear). I ran inside to get my husband and he came outside with me and saw the object. I’m absolutely kicking myself because I couldn’t get to my binoculars in time to get a closer look.
 It seemed to be at a high altitude and moved across the sky not quite as fast as the ISS but faster than a high altitude airplane.  Neither of us has ever seen anything like it.  I’m sure there’s a rational explanation.