I was thinking about the working principle of propeller aircraft (piston engined) during some dark night hours with nothing to do... Mostly because of flight simulator video games hahaha... Basically for the piston engined propeller aircraft (P-51 Mustang) to move forward, the propeller must be engaged correctly with regards to the powerplant. The propeller is the actuator of flying at the end of the day. The blades must move the air in a certain way, in order to create thrust. Is this last sentence correct? The propeller blades must be angled properly. And there must exist enough the necessary energy (petrol), to fuel the powerplant and actuate the propeller blades. Propeller blades cause the thrust to occur due to Newton's third law and atmosphere filled with nice chunky gaseous substances. Now if we think about something like an F-15 aircraft with turbofan engine... The principle of flying never actually changes. The fanblades become the same as propeller blades in ancient aircraft. Basically fanblades assume the role of previous propellers. Isn't that the true reason why something like turbofan engine works? There must be logical reason what causes air to flow, into the turbofan engine, in the first place. Could somebody elaborate. Imagine that an F-15 aircraft is sitting still on the ground not moving anywhere. Aircraft rests on its wheel on the runway. Engines are not running. Air is NOT flowing into the engine when engine is not running. OK, now the F-15 pilot engages the engine starter. Engine starts spooling up the fanblades (somehow). Now airflow begins to flow inside the engine?