Passengers may be carried and flight in furtherance of a business is technically permitted; however, a private pilot may not be compensated in any way for his services as a pilot and must pay at least his pro rata share of a flight's expenses. Neither passengers nor cargo may be carried for hire.
Operation is limited to those classes of aircraft in which proficiency is demonstrated and required experience is acquired. An example of such a class would be airplane, single engine, land (ASEL).
In the United States, Private Pilot's Licenses are issued for life; however, additional requirements must be met to exercise most of the privileges the license grants. For example, a valid medical certificate must be held and these are issued for period of two to three years. To carry passengers, a private pilot must have made at least three landings in the past ninety days.
Some aircraft require additional ratings. For example, any aircraft with retractable landing gear or a fixed-speed propeller requires that one have demonstrated competence in such an aircraft.