The complexity of getting a airplane to hover then start moving forward then stop moving forward and resume hovering and the amount of stress that puts on the frame of said airplane are a large reason. You can’t forget when the plane is hovering the wings don’t generate lift so your using the eng to completely lift the plane off the ground in a controlled manner. All a normal plane has to do is move forward fast enough to have the wings lift the plane off the ground. The engine them self don’t actually push the plain up so much as forward let alone be the main source of directional control.
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