They are an important part of the aircraft that makes it fly. There are many other parts without which the airplane cannot fly.
Hollow bones
on the wings
yes if its attached to a propeller/ rotor blades and or has wings for flight..
Lift from the wings and thrust from the engine.
Human Flight is only possible with the aid of a manufactured Mechanical Device. True FLIGHT (not Gliding) requires an Airplane (or Helicopter) of some design. Whether or not the "ENGINE" is mechanical or Human, the Human is not "Flying" in the sense that a Bird Flies.
There is a lever inside the cockpit which allows the pilot to fold the wings to minimze the footprint of the aircraft when parked on the flight deck of an aircraft carrier.
Aircraft wings can move up and down as part of the normal operation of the aircraft. This movement helps to control the flight of the aircraft by adjusting the lift and drag forces acting on the wings. The wings can also move as part of the aircraft's flaps and slats system to change the wing's shape for takeoff and landing.
If it has multiple engines, an aircraft can remain in a stable condition (level flight) if one of the other engines fails. It can do that because the power of that/those functioning engines is enough to do the job of keeping the aircraft in the air. If an aircraft has a single engine and it fails, there is very little possibility that the aircraft will remain in the air for very long, if at all. However, even with power off, it is possible to maintain the aircraft in a stable condition (wings level) as it descends to the earth. A power outage has little or no effect on maintaining a single engine aircraft in a stable condition. The flight controls still function, albeit with markedly less effectiveness and authority. This is all possible because lift is a function of speed. As long as the aircraft's airspeed is above stall speed, it can fly. But a heavier-than-air craft with its engine/s out will not fly more than a few minutes, depending on altitude. During flight training, pilots are taught procedures to do in case of loss of power at altitude.
The net lifting force on the wings of a jet remains constant during level flight unless the pilot adjusts the angle of attack or the speed of the aircraft. In a steady flight condition, the lift on the wings equals the weight of the aircraft.
Aircraft consist of a few major sections, the Wings, Empennage, Flight Controls and Fuselage. As the speed of the aircraft increases winds travel under the wings at a faster speed then going over the wing causing Lift. As long as there is enough lift it causes the Aircraft to fly.
Gravity is the force that pulls an aircraft towards the ground, acting against the force of lift generated by the wings in level flight. Gravity pulls the aircraft downward, while lift generated by the wings counteracts this force to keep the aircraft aloft.
In flight, lift and weight act in opposition to each other, with lift generated by the wings counteracting the force of gravity acting on the aircraft. Similarly, thrust and drag act in opposition, with the engine propulsion providing thrust to overcome the drag force caused by air resistance on the aircraft.