We were up at the local school playground and we noticed two cross-like objects that looked like a plane but surely was not a plane. No FAA lights, no contrails, just white cross-like. They looked stationary in the air, but moving in a North/Northeast direction. We are 10-15 miles north of the Sioux Falls airport, so we do are very familiar with commercial and private air traffic. This was not plane activity. I've been deployed and have seen airborne military drones in person, in observation and in action in theater, and they somewhat resembled them, but did not look like it.We observed them from the playground until they were out of sight because the school was in the way. The way that the two objects moved in the sky was not that of a moving, propulsion plane. It looked like they were floating yet moving through the sky, but not at a very fast rate that you would normally see a flying object at that height in the sky.