Unmanned aviation has leapt many technological hurdles in recent decades with UAVs proving their worth with devastating effectiveness in recent and current conflicts.
However, arguably the biggest opportunity for the sector remains the civil arena, and here technology - including automatic collision avoidance systems - and public and political concerns are among the challenges that must still be overcome.
In the following special feature, we look at some of the early steps being made towards UAVs becoming a common sight in the skies over our cities in roles such as law enforcement and crowd monitoring.
Meanwhile, back in the military sphere, we take a look at two of the key UAV programmes: the UK's Watchkeeper surveillance system and the USA's long-endurance Scan Eagle.
More features on the UAV sector