The maneuverability of the dragonfly, the firefly's ability to generate light at one hundred percent efficiency, the owl having the most silent flight among all the bird species: The characteristics many creatures have that are similar to these have long fascinated people for centuries. So much so that these characteristics have been an inspiration to particularly scientists, leading to the emergence of a new scientific field.
References: http://www.livescience.com/57247-ways-animal-flight-inspires-drone-designs.html