Plus it isn't just airplanes that get airborne. Some animals can do it while others manage to glide through the air. Amazing.
So how do they do it? Well it's all about air pressure as Bill Nye explains in his video on Flight (I've included my Bill Nye Flight worksheet as well as a YouTube video link free of charge HERE). If the pressure below the wings is higher than the pressure above them, the plane goes up. If the plane is being pushed forward (thrust) by it's engines with a greater force than than the force which is holding it back (drag), it will move forward. Planes utilize this forward motion to generate the difference in air pressure needed to get the plane off the ground (create lift). Gravity acts downwards and so you need to generate enough lift to overcome it. Again, this comes down to air pressure difference. I have an inquiry lab on TpT (free) that you might be interested in.