The 33-year-old was last seen on Clarendon Street, Derry on Friday, May, 10 at 5 pm.
A police spokesperson said: “He is described as being approximately 5’8” tall, of medium build.
“He is believed to have been wearing blue jeans, dark navy jacket and brown loafers.
“We are appealing for Aidan to make contact with police or his family.
“Or if anyone knows of Aidan’s whereabouts please contact police.
“They should ring the 101 number quoting reference 800 of 12/05/19.”