The department is drafting a policy on how it will use the remote control aerial vehicles.
A Thursday evening question-and-answer session about the drones became heated when members of the public spoke out against the technology.
"I'm not really surprised that people are upset. It's a frightening thing to think that there's government surveillance cameras overhead," said Jennifer Shaw of the American Civil Liberties Union.
Police have said they expect to use drones in search and rescue, accidents and natural disasters, and unusual crime scenes.
Aerial drones can be as small as a hummingbird or as large as the lethal Predators and Reapers used by the military in the Middle East and Asia.
Seattle police plan to use the mini-helicopter Draganflyer XG made by the Draganfly Innovations company of Saskatoon, Canada,
It is operated with a hand-held controller and joysticks. It carries cameras that can take still pictures, videos and infrared shots. It is limited by a battery life of less than 10 minutes and an inability to carry more than 35 ounces - a little more than 2 pounds, police said.
The FAA has guidelines on how and when law-enforcement agencies can use drones. They cannot be flown at night or over crowds. The drones must be flown below 400 feet and must remain within eyesight of an operator as well as an observer at all times, according to the FAA.
Despite those guidelines, many at Thursday's public event suggested the police department would abuse its power.
"We all know this will be used for political suppression," one person said.
The law enforcement use of drones prompted an ACLU review that found existing laws and policies are inadequate to safeguard citizen privacy.
View the proposed operations manual here >>