We've all heard, and probably believe this explanation of how a wing works: airflow is split at the leading edge of a wing, that part of the stream which flows over the top curved section of a wing must flow faster over the longer surface than air moving over the lower straight surface, and the split stream meets up again at the trailing edge of the wing. This is what generates a pressure differential- the pressure is lower on top thereby generating lift upwards.

University of Cambridge's Professor Holger Babinsky was so frustrated that everyone seems to believe this that he thought he should demonstrate that it is absolutely wrong:

"I don't know when the explanation first surfaced but it's been around for decades. You find it taught in textbooks, explained on television and even described in aircraft manuals for pilots. In the worst case, it can lead to a fundamental misunderstanding of some of the most important principles of aerodynamics".

"What actually causes lift is introducing a shape into the airflow, which curves the streamlines and introduces pressure changes—lower pressure on the upper surface and higher pressure on the lower surface. This is why a flat surface like a sail is able to cause lift—here the distance on each side is the same but it is slightly curved when it is rigged and so it acts as an aerofoil. In other words, it's the curvature that creates lift, not the distance".