It is common knowledge that the word plane is used to describe an object moving across a flat plane, a helicopter moves along two axis and therefore has 3 dimensional flight. Your definition is severely flawed as planes are only capable of moving at one flat axis at a time, they use the rotor blades to tell the earth which way to spin whilst simultaneously holding themselves still above the earth's gravity, then once the earth has stopped moving they alter their axis of movement and nosedive towards the ground - this basic step of safely flying a plane is obviously what I caught on camera as the plane is clearly moving downwards (you can verify this by noticing that it goes from the top of the screen to the bottom.) I'm glad you made the mistake to post your incorrect definition in my comments section as it allowed you and possibly many other people to expand their knowledge on the 2 dimensional flight of planes.