Villa Bee Fly
Tau Emerald (Hemicordulia tau)
Retired Professor of Anatomy, Ian Gibbins, has kindly shared his thoughts with us to help people learn:
Some insect flying is incredibly efficient: some with high wing-beat frequencies (I can't remember which off hand, but include some flies at least) use the thoracic exoskeleton as an elastic resonator so they only need to contract the flight muscles every few wing beats. I think dragonfly wings have cantilevered joints so that the flight muscles don't have to work against as great inertial resistance as they would otherwise.
Beyond the biomechanics, the flight muscles of insects with high wingbeat frequencies, which includes blowflies and hoverflies, have the highest efficiency of converting chemical energy into mechanical energy of any known organism.
There are also some pretty fancy mechanisms for saving energy in the legs of some species, eg the jumping mechanisms of grasshoppers and fleas (which are are different in detail, but similar in principle). But most insect walking doesn't involve such things.