There is 1 Dead Ghosts to be found in Aerodrome. They can be collected on the mission The Coming War. Each Ghost can only be collected once per account.
Ghost 1[edit]
Head through the Aerodrome until you reach the broken bridge that you must cross. Stop and look to the right, back toward the entrance of this area.
Head over to the edge and stand on the railing near the wall. Jump over to the Dead Ghost from there.