Could a commercial pilot please take us through the following for clarification, which I'm sure has already been covered in the great morass of this thread's history?
Air Traffic Control: Routes are segmented, aren't they? In other words, the pilot's last words were "All right, good night." What was said by ATC in the previous transmission, of which this was the answer? And doesn't it follow that at the time when leaving one segment of ATC, and being handed off to the next, that there is a change of radio frequency, with the next segment expecting the transponder I.D. Wouldn't the a/c be queried by the next ATC? Or does it fly into a blank distance with no ATC? At some point, ATC somewhere must have been calling them repeatedly.