Unmanned aerial devices aren't just getting more common. They're also getting smarter.
Case in point: The Remora, which is a small UAV that attaches to a larger UAV and can be deployed upon command. It's pretty much a small, weaponized remote-controlled airplane bomb.
Remoras can be attached to larger drones, such as the Predator, and separated when the target is within range. Once the operator "dislodges" the Remora from its mothership, it's remotely controlled by a pilot until the target is reached.
The first generation of Remoras are relatively large. But perhaps one day Remoras will have Remoras of their own--and the skies will be filled with UAVs.