the object was oval shaped and at the tipical attitude of small planes no distinguishing features no sounds

not sure of date ,incident happened during warm months probably April or May 75 or 76 in northwest Florida,while driving home from work on a very clear afternoon ,I observed an oval shaped dark colored matalic grey object moving acrossed the sky at aproximately the hight that small planes usually fly.
Initially I thought that it was a small plane but when I looked directly at it I realized that it was just a dark oval shape moving in the sky.  It made no sounds and had no distinguishing features.  
After a few seconds it as no longer visible to me. 
There was one passenger in the car who also saw the same thing.We agreed not to tell anyone for fear of  being ridiculed but we know that we saw it.
Witness indicates that date of incident is approximate.  PD