Aerospace engineers have designed a hovering craft that mimics the spiraling pattern made by maple tree seeds.

Called RoboSeed NAV (nano air vehicle), the craft has a maximum dimension of less than 4 inches (9.5 cm), making it the world's smallest controllable single-winged rotating aircraft. Other flying craft may be smaller, but they have more than one wing and are symmetrical, according to the engineers who built RoboSeed.

The team also built scaled-up versions of their one-winged crafts, which have more maneuverability.