There really is no difference, robert. The only distinction between a model airplane and a SUAS ("small unmanned aerial system) is that one is used for recreation, and the other is used commercially. In order for an enterprise to operate a SUAS, a COA (certificate of authorization) is required. This requires the organization to jump through many hoops, and currently a business cannot use the system for profit. It's used for research instead. Local governing bodies are not exempt from the COA requirement. Hobbyists can fly a SUAS under AC 91-57, because it is for recreation and is thus considered a model airplane.

NorfolkSouthern