Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
It is not true that air takes the same time to travel above and below an aircraft's wing. This misconception, illustrated at right, is widespread among textbooks and non-technical reference books, and even appears in pilot training materials. In fact the air moving over the top of an airfoil generating lift is always moving much faster than the equal transit theory would imply, as described in the incorrect and correct explanations of lift force.