Yesterday we had a beautiful warm day 20 degrees C! (68F). We went out biking and I spotted this person high in the sky. I thought it was a parachute but it didn't came down and I heard a motor. I had never seen this before so I googled a bit and it is "Powered Paragliding" (PPG). You have a backpack motor connected to a big spinning propeller. Look here how it looks like.
See for more skywatches here