FAR 91 operations only require a Private Certificate as a minimum req. If 0ver 12,5 in weight or turbojet powered, then a type rating is required. Thereafter, only a biennial flight review. These are the LEGAL mins. OF course, this would never happen in the real world, with insurance and other factors. So no ATP or even Commercial certifiacte is required per FAR. So yes, El Capitain is correct.