Hey folks. Saw an unusual (for 2018) airplane in flight today and trying to figure out what it was. Large straight wing airplane with four prop or turboprop engines. Tall vertical tail section with a structure hanging off the back that looked like it was for in flight refuelling. Gray or silver in color, couldnt make out any numbers or insignia. Overall, I think it looked most like an old USAF KB-29 or KB-50 tanker. I saw it flying southeast over Lexington, KY around 1:10 pm. It did not take off or land at our airport, as I saw it North of the airport and then again south of the airport some 10 minutes later as I was driving down I-64. It was flying right at the cloud cover, I would guess around 8,000 feet. Anybody know what airplanes that look like that are still flying today?