The MPL doesn't allow the holder to fly as Pilot-in-Command, although in a pinch he probably could do it. It's a basic ticket to allow a non-ATPL pilot to fly as a fully qualified crew-member of an aircraft that otherwise requires the full ATPL ticket. Elsewhere the pilot would likely be accumulating only solo experience, and he won't be much use when transitioning to a multi-crew airplane. The MPL only allows the holder to act as copilot, 2nd officer (flight engineer) or cruise pilot, not as PIC, on any flight including to the USA. Where it's used, the MPL holder will be granted his ATPL when he completes any additional regulatory requirements and has accumulated the required hours. The MPL pilot is entitled to fly in his aircraft as co-pilot from anywhere inoutside the USA into the USA, although not in a USA-registered aircraft. Some pilots start their MPL training after completing A PPL or CPL beforehand.