Have you ever wondered how planes fly? So you're sitting on the nice green grass then you suddenly hear a sound like a plane, you see a big plane up in the sky and immediately think how on earth does it fly.
Thrust is the force that works against drag and moves the plane forward. Lift is the force that is directly opposite to the weight of an airplane and holds the plane in the air. Weight brings the plane down to the ground and drag is the force that slows the plane down.
How planes get off the ground is because of thrust and lift. Lift brings the plane in the air and thrust moves the plane forward. How planes stay in the air is because of lift and thrust.
How planes land is because of weight and drag. Drag slows the plane down and weight brings the plane down.
So in conclusion it is obvious that airplanes need to have the four forces which are lift, drag, thrust and weight to fly.