Large silver-gray object hovering over ground as seen from small aircraft

I was flying a Piper PA-22 aircraft from Colts Neck Airport (now closed) in NJ. While practicing standard-rate turns at about 2-3,000 feet altitude near the beach east of Colts Neck (probably north of Long Branch) I saw what I first took to be a stationary blimp below me, but I didn't notice any tail fins. Each 360 degree turn took 2 minutes and so I could only see the object every 2 minutes from a certain position in the turns. The second view confirmed my impression that there were no tail fins, markings, lights, tethers, gondola, engine pods, or other features of a typical blimp or balloon. The 3rd view confirmed that the object was hovering above some thin coastal fog and not resting on the water or ground. It was definitely not a cloud or reflection, but a large 3-D object, metallic silver-gray, and from my angle shaped somewhat like a blimp as seen from the side. My estimate of size was about 200 feet long and possibly bigger. Despite the size, shape, and the fact it was hovering; there was nothing actually confirming it was a lighter-than-air vehicle. When I came around for the fourth turn the object was nowhere in sight. I looked around for it as I headed back to Colts Neck but couldn't find it. Considering its size, this seemed fantastic because I had extraordinary vision and probably could have spotted it 50 miles away.