This is a US Strategic Command (formerly SAC) aircraft -- possibly the Looking Glass -- leaving for a trip to who knows where. It used to be that there was always one of these in the air, ready to serve as an airborne command post in the event of a nuclear war/crisis. I think they discontinued the 24x7x365 stuff, but don't know what's been the policy since 9/11. I was stationed at SAC Headquarters (near Omaha) when I was in the Navy (that's another story) and knew many of the guys who flew or staffed these planes. Over time it became quite clear what an awesome responsibility was vested in a single aircraft. Sometimes it seems like those days were so much simpler.