Lentink's group studies biological flight as an inspiration for engineering design. We focus on key biological questions which we probe with new engineering methods to find inspiration for innovative flying robots. Our comparative biological flight research ranges from maple seeds and insects to birds such as swifts, lovebirds, and hummingbirds. For in-depth biomechanics research we focus on bird flight. Our fluid mechanic research of dynamically morphing wings ranges from studying vortex dynamics to fluid-structure interaction. We apply our findings through robot designs centered on flying in complex cluttered environments under realistic atmospheric conditions.