SAS stands for Special Aircraft Systems, Inc., an FAA Part 135 On Demand charter freight company. It was owned and operated by the late Robert Ruhe and his son, Eric Ruhe. The operation was based at the Ruhe private airport (with a paved 5,000+ foot runway, a sizable maintenance hangar and fuel farm) on the Ruhe farm, located in Leipsek, Ohio, near Toledo. They operated a small fleet of renovated and converted EMB 110 aircraft. They also had an FAA Certified Repair Station (CRS) for overhaul of the Pratt-Whitney PT-6 turbine engines used in both the EMB 110 and agricultural aerial application aircraft they operated. They still operate the Ag aircraft for crop dusting, operating as Ruhe Agr. service.