Vortexes

If you look closely when you are near or behind the wing in an airliner you can see it a bit when the air is moist. It's like a white curling mist on the edges of the wings. Looks pretty cool. In windtunnels they add smoke on purpose to see these vortexes since this has to do with drag and lift. Basically that which makes it fly. You see it also in Formula 1! Only then you want to keep the car on the ground so it goes a bit differently. The turbulence which creates the vortex can actually be quite dangerous as well. You can have a sudden drop in altitude and that is something you wouldn't want during take-off or landing. It's all about wind flow and aerodynamics actually.