Sometimes you just want to fly, or you are new to flight simulation, and don't wish spend 30 minutes preflighting an aircraft. Maybe today you don't want to spend much effort to create a flightplan and programming a flight management computer. feelThere LE aircraft are designed to be detailed enough to immerse you in the simulation experience and quickly get into the air from power-up to takeoff. Many systems are modeled, just not every system. You will find the level of detailed is greater than any flight simulator default aircraft. The systems that are modeled behave correctly; or are only slightly simplified. LE aircraft are designed for fun which is the point for playing Microsoft's Flight Simulator.