I would suggest that you clarify your needs a little more - design, maintenance, flight systems, navigation systems, sensor systems. You also may want to think about what activities you will hire full time engineers, outsource to a company, or use temporary people. And there is always the idea of using other people's technology. Determining how to best develop a product in a startup (which is what I think you are really asking) is complex, and requires a lot of thought. We have several white papers on the subject on our website.