Originally Posted by
runway30
In my scenario, the PIC is choosing the aircraft on behalf of the company.
Even then the PIC might not automatically become an air carrier. If in my last example a company tells me that the plane they usually use is unavailable, and if I perhaps could find them a different plane and maybe fly that myself then they still have full control. Their flying date and time, their destination, their passengers, all costs paid by them, their final decision on plane and pilot.