From technical point of view I think the airplane flies thru the turbulance, the turbulance is local in the air heh.
I'm not aware of the way it is usually said in English, but that's the way we say it in Romanian and seems to have been translated word by word.
In English we would say either the plane flies in turbulence or, better still, the plane flies through turbulence. The turbulence is a property of the air the plane is flying through. Captains on flights usually announce "We are experiencing turbulence - please fasten your seat belts."