They are now a familiar presence in war zones, but if manufacturers have their way, skies over civilians heads will soon be busy with unmanned vehicles.
Drones are currently a growth industry in the aviation sector, with scores of new companies competing for a slice of the market.
And if they can clear hurdles that currently limit their deployment in friendly air space, pilotless planes of all shapes will be taking to the air on missions to watch over us.
Some of the aircraft -- from devices barely bigger than a paper plane to formidable missile-sized systems operated by five-man ground crews -- were on display this week at the UK's Farnborough Airshow.
Although the event, held on alternate years, is one of Europe's biggest market places for traditional aircraft, a "drone zone" occupies a substantial slice of the exhibition space.
"There now are hundreds of companies competing for the market," said Konstantins Popkis, chief technology officer for the UAV Factory, which produces a 3.3-meter wingspan drone known as Penguin B.
"But not all of them are producing reliable systems," he added...