Flying unmanned Predator and Reaper aerial vehicles for the Air Force used to be a job for trained (manned) aircraft pilots, but that is changing. Previously, pilots would rotate from manned aircraft to unmanned aircraft for a period of three years before rotating back into the air, but demand for UAV pilots has caused the Air Force to seek full-time career UAV pilots not otherwise trained to fly manned aircraft. Currently a program set in motion to train such officers is seeking to recruit non-pilots as UAV operators -- the staffing transition may take up to four years. The military is outsourcing some of the training and the University of North Dakota, which has set up a UAV center -- the Unmanned Aircraft Systems Center of Excellence -- and has received a $50 million training contract from the Air Force. Currently, there are over 100 Predators and Reapers in service with over 200 crews supporting them. UAV pilots have been enabled by new equipment to handle multiple aircraft at the same time, but in practice pilots rarely handled more than two well.