Maple samaras are seeds with papery wings. When I was a kid, we used to collect maple samaras to play with. Some were big, and when you opened up one of the seeds, they were sticky - sticky enough to put them on our noses and pretend we were rhinoceroses. A better game was whirlybirds. The samara is perfectly designed to helicopter from a tree to a distant location. That paper wing helps it fly, so it can find a place to grow beyond the shade of its parent tree. They are built for seed dispersal.
When you find some maple or ash samaras, drop them from a height and measure how far they travel. Or toss them in the air and watch them twirl their way down.
If you're adventurous, try snacking on maple seeds. They're a bit bitter, but the folks over at Eat the Weeds suggest leaching them before roasting.