Traveling NW by car from St. Paul we saw what we originally thought was a huge cluster of balloons. After watching for a couple minutes we realized they weren't balloons, or birds, or anything else we've seen before. They were reflectting light, then they would all disappear, only to show up again a few seconds later. We pulled over so I could try to get a couple pictures but only managed to get one. These orbs would form various shapes (triangles at one point) then very quickly change to a different formation. We saw one plane fly directly below them. We followed them home and walked down the street to watch them until they were too far away to see anymore. Black hawk in the area about an hour later.