If you’ve ever flown coast to coast or around the world, perhaps you wonder, as “Future of Everything” host Russ Altman did recently, whether engineers know how to design small drones for purposes like delivering goods and/or performing services in urban airspaces.

But as Stanford mechanical engineer David Lentink explains, the physics of flight change unfavorably when aircraft get small. That's why his lab studies nature’s aviators: small birds, including some migratory species that weigh less than a cell phone. Their tiny frames pack enough energy to fly from Alaska to New Zealand, nonstop. Learn more about his research on the Future of Everything radio show.

You can listen to the Future of Everything on iTunes, Google Podcasts, SoundCloud, Spotify, Stitcher or via Stanford Engineering Magazine.