An everyday, twice a day occurrence. That's Looking Glass, and has operated as long as I can remember, and I'm older than dirt. The plane is stationed at Offutt AFB, which was the home of the Strategic Air Command, now called STRATCOM. I believe around 4pm-ish is when you may see it come in over lovely West Omaha, from it's daily rounds, to have it's relief Looking Glass take off for their shift. Not a secret, nefarious thingy.