With a Private Pilot License (PPL), you are generally limited to flying single-engine, non-commercial aircraft. If you want to fly more complex aircraft, such as multi-engine planes or higher-performance aircraft, you will need additional ratings or endorsements. For example, if you wish to fly multi-engine aircraft, you must undergo specific training and pass a check ride to get a multi-engine rating. Similarly, to fly certain types of aircraft like seaplanes or helicopters, you would need the appropriate type ratings.