The plane the boy is seated in is called an "Ultralight" Aircraft. It comes in a kit, if desired, for the mechanically inclined person to assemble. The wings are normally made out of sailcloth. The one I had and flew had an old VW engine with about 50 horsepower. The pilot is limited to how fly he can fly and other rules of the sky, like you can't fly within 'x' miles of an airport. I forget all of the rules. I had mine back in 1986. It was a lot of fun, but the best days for flying this type of plane is a windy day. My plane was a 1-seater, but you can buy a 2-seater.
According to what I googled, the cost is about $8-15,000. I paid $3600 for mine back in '1985, but that did not include the motor. After I had studied the plane and then looked at similar sports crafts, I determined that it was basically a hang-glider with an engine. Lots of fun and back then, no license was required. I don't know about today. I flew in and out of a private runway on a farm made out of dirt.