I recently returned from a deployment, and a major airline was chartered to bring us home in a B777. Since we were all military, we were allowed to sit in one of the two jumpseats and chat with the pilots as much as we like. I got to sit up there and talk flying with the pilots for a good 2 hours. That FD is incredible BTW.
For civilians on a normal airline flight, I can't imagine that anyone would ever be allowed up there in light of current events.