I live near Michigan Stadium so I often see interesting aircraft flying overhead: Fighters, bombers, a presidential helicopter squadron.
This afternoon I heard an obvious loud engine indicating a fast-mover overhead. I went outside and sure enough a plane with wing-tip pods was flying around the stadium in a wide circle that took it over me.
Sadly, I forgot my camera. It had straight wings and pods on the wing tips. And a conventional tail section. Single engine. I didn't notice what the air intakes looked like.
Funny enough, I thought it was flying inverted for a while, so I think it had some sort of bubble near the nose under the plane. Cameras? Sensors?
If flew off to the east, I assume to Selfridge Air National Guard base.
Perhaps I'll see it tomorrow during the Michigan-Notre Dame game. Right now I have no idea what it is.
UPDATE: Black Diamond private jet team will do flyover before game. Could I have seen an L-39 Czech trainer? Paint job didn't seem like what their colors are, though. We'll see.