Grumble — both this site and the newer one someone else posted [1] link to an old and somewhat misleading diagram of how an airplane wing works [2].<p>The problem with the diagram is that the "lines" both ahead of the wing and behind the wing are pretty much flat — as if the air ultimately returns to where it was as the wing moves through it (to be fair, the lines are a little wobbly in the diagram).<p>That's misleading because if the wing has a net force upwards (ie lift), then the air must have a net force downward. You can't invent forces out of thin air (literally, in this case :). Yes, there's Bernoulli’s principle and all that, but fundamentally: if the wing is pushed up, then the air must be pushed down. The mechanism for how that happens is a separate discussion.<p>This is an issue that has been debated back and forth for a long time, so I don't want to re-hash it in this comment, but I think it's fair to say at a minimum that those diagrams are misleading, and fly (ha) in the face of Newtonian laws of physics.<p>I expect better from NASA.<p>Here's good short Veritasium video on the subject: <a href="https://youtu.be/aFO4PBolwFg?t=13" rel="nofollow noreferrer">https://youtu.be/aFO4PBolwFg?t=13</a><p>Also good: <a href="https://www.youtube.com/watch?v=HmDYbnGnhpA">https://www.youtube.com/watch?v=HmDYbnGnhpA</a> (part 1), <a href="https://www.youtube.com/watch?v=21YB4qCvIK4">https://www.youtube.com/watch?v=21YB4qCvIK4</a> (part 2), <a href="https://www.youtube.com/watch?v=iE27CXLXbp0">https://www.youtube.com/watch?v=iE27CXLXbp0</a> (part 3)<p>[1] <a href="https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/" rel="nofollow noreferrer">https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/</a><p>[2] <a href="https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/aerodynamic-forces/" rel="nofollow noreferrer">https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/aer...</a>