From that page, I now know that the mistake shown in the xkcd comic is called the "Equal Transit-Time Fallacy". There is no requirement for an airflow, once se

From that page, I now know that the mistake shown in the xkcd comic is called the "Equal Transit-Time Fallacy". There is no requirement for an airflow, once separated, to speed over the top of the wing to match the airflow underneath. In fact the top-layer airflow moves faster than the bottom layer, and arrives at the trailing edge sooner.