The physics of flight scale with wing size and air speed. Small and slow-flying animals are characterised as low Reynolds number (Re) flyers while large and fast aircrafts are typically at high Re. We are interested in wings operating at low to medium Re where gliding is possible and yet not quite the same as what we know for gliders. Flying things in this range includes, butterflies, dragonflies, and some paper airplanes. Wings at this scale tend to be flat, cambered, and inevitably flexible. How do we maintain the structure without adding thickness and weight? Can we modulate the stiffness of the wing simply? What advantages can we take from the wing compliance? These are questions that insect wings can tell us.
Compared to the airplane wings, dragonfly wings employ various corrugation to give structure integrity and directional compliance.