A former US Air Force drone operator has described how he is haunted by his time as a ''remote killer'' functioning in ''zombie mode'' in missions over Afghanistan and Iraq that claimed more than 1600 lives.

Brandon Bryant, a retired airman who operated remote-controlled Predator aircraft from US bases in Nevada and New Mexico, offered a rare military insider's perspective on the US drone program in GQ magazine.

An unmanned US Predator drone flies over Kandahar Air Field in southern Afghanistan in 2010. Credit:AP

He described monitoring a drone strike on a mud compound in Afghanistan and seeing the figure of what he was certain was a child just before it was struck by a Hellfire missile.

When he expressed those concerns to an intelligence observer overseeing the operation, the response came back: ''Per the review, it's a dog.''