Witnessed a black triangle flying south around 15-20 thousand feet while putting out my cat. seen it for about 5 seconds as it flew between clouds and i got a real good look at it. i am very familiar with aircraft and this looked like the tr3b i have seen on youtube but it had no lights and was a lot bigger. it had to be as big a commercial jet airliner. i heard no sound but i can’t hear a jet airliner that high either.