In the past few years, we have seen a couple of innovative robots that can turn into drones to fly over obstacles and transport items. This 3D printed robot from Michael Rechtin is also worth a look. It shifts from a tank like rover into a quadcopter. As you can see in this video, the robot unfolds its wheels, which hold the rotors it needs to fly around. When on land, it changes its posture to roll around.
These features enable this robot to navigate in rough, unpredictable terrain. You can find out more here.