US military tests a Tinker Bell-sized drone

There's no standard set for the shape or form of drones, and the Army plans to use that to its advantage. Here's where the Black Hornet Nano comes in. This micro drone, designed by Norway-based firm Prox Dynamics, is small enough to fit in the palm of your hand, measuring in at a mere 4 x 1 inches and weighing only around 0.04 lbs. What's more, the PD-100 UAV features regular as well as thermal cameras and has a range of roughly 0.6 miles -- in other words, it's perfect for those missions that require stealth surveillance.

According to Defense One, the US Army has "a handful" of these drones in its possession, which it began testing back in March. That said, the tiny, $40,000 Black Hornet Nano has been part of the British military's arsenal since 2013, so the US is a slightly behind on adopting the device.