Indoor Version:
We laid out a blanket and taped off a runway and a landing area. We made and decorated several paper airplanes and then Rowin had fun trying to throw/fly the planes so that they would land inside the landing area.
Impressive, right? ;)
Outdoor Version:
If it's nice outside, you can do the same idea with chalk in your driveway. We made a few runways, helicopter landing pads, and an airport. He was in his own little airplane world for the longest time.