To start to fly you needspeed and thrust. When you take off you create lift to start to fly. I am going to tell you how to create lift.
The forces acting on a plane are thrust , lift, drag and weight. Thrust makes the plane move forward to create lift. Dragand weight allow the plane to fly in a stable way. Drag and weight help land your plane, when you create drag you create weight.
You need speed to create lift andwings are different shapes and sizes. Some wings have propellers on them so it creates more thrust. Other ones have flaps to create dragand to be able to turn and stay balanced.
Air pressure can be used in different ways. Air pressure is when you are flying and go up. Air pressure is bad whenyou need to land quickly because the air pushes you up.
To create lift you need speed and thrust.If you have the right body and wings you create air pressure and you can fly.