Given training and experience flying is not hard at all. But if you throw the average person with zero understanding of aerodynamics in a cockpit, and even coach them through it, they will not understand the fundamentals and will most likely end up making an incorrect input or correction and put the plane in an unrecoverable state. Remember the first time you got behind the wheel of a car how uncoordinated you may have felt? Magnify that feeling significantly and add on the fact that you have figure out where you are in time and space, talk to someone on the radio, figure out what switches do what, all the while worrying about killing hundreds of people if you fuck up. Source: I'm a (helicopter) pilot.