In the future, it's possible that some unmanned aerial vehicles (UAVs) might sport wings that flap like a bird or a butterfly. The Army Research Lab has been testing such a UAV, known as Robo-Raven.
Robo-Raven has two motors that independently control each wing. There are commercial flappy-bird designs that work more efficiently using just one motor to control both wings. But from a scientific standpoint, this approach lets one learn more about the platform and explore interesting spaces of the design, which wouldn't be possible with a traditional flapping wing single-motor design. With a single motor, one can only speed the wings up and slow them down, which doesn't do much to inform learning of the system.
A more robust Robo-Raven will carry a full suite of sensors that will measure altitude, air speed, wing position, flapping speed, power draw, battery charge, acceleration, and roll. The Army might come up with an innovative flexible material that would boost the chance of bird-like flight.