Video of the event posted on Monday shows the drone being loaded with flyers containing information about Intelexit – an organisation that aims to help spy who have “moral problem” with their line of work to get out.
The drone then flew over the Dagger Complex in Darmstadt, Hesse, and released its cargo into the high security US military installation below.
“We know from an informant that people read the leaflets and that access to our internet site was then blocked for computers inside the base,” Ariel Fischer, one of the Intelexit organizers told The Local.
The use of a drone to carry out the action had a strong symbolic quality said Fischer.
“It is a dangerous threatening tool and normally a symbol of fear – but it was turned into a purveyor of hope.”
According to Fischer, Dagger is a “critical artery” of US spy operations in Europe.
“Without the Dagger Complex – and without Germany – they would not be able to carry out the level of mass surveillance they do,” said Fischer.
Reports in the German media suggest that 1,100 NSA employees work at the installation, from where massive amounts communications are tapped with tools such as XKEYSCORE, a software which monitor's people's web history.
The Intelexit campaign is currently focusing on spies in Germany, the UK and USA.
Activists have tried to raise awareness of their services by putting up billboards outside intelligence facilities such as the UK's Government Communications Headquarters (GCHQ).
By employing hackers the anti-spy group have also been able to obtain personal details of intelligence workers, whom they then approach by telephone.
It is early days – the campaign kicked off a week ago – although they are still to persuade their first spy to come in from the cold.
“There have been people who have contacted us. But as yet no one has decided to take action,” said Fischer.