Driving north on route 16 in dover. first sighted at 9:52am after the toll booth between exit 6 and 7. viewed at about 40 degrees in the sky to the north. appeared as a black line with slightly curved edges. not to read into it, but my first thought was this is the black line that could separate the top and bottom of a flying disc. disc was not visible though. did not move as normal aircraft, but moved very slowly, sometimes stationary. i also thought that perhaps it was one of those long balloons that clowns twist into animal shapes, but the line did not undulate with the wind, and also did not move as fast as a balloon or in one direction. also it was visible behind clouds that appeared to be very high in the sky, which made me think it was quite large. the black line slowly rotated from horizontal to angled to vertical, which made me rule out a drone which typically has to fly so that it's fans are parallel to the ground. from my vantage point, it moved first to the w slightly then up and to the n/ne getting smaller and smaller until it seemed to be disappearing behind cloud cover. then it moved slightly closer and started to move ne/e and down below tree line. it was lost behind the tree line about 9:10/9:15am. there were two times where the line slowly transitioned to a red/orange color and then back to black as if the angle it was rotating caught the sun's reflection. i was in the car so i could not hear a sound. it never landed. i took a couple photos and a short video. it should have been close enough to the pease airport radar to be picked up.