If you want to satisfactorily explain this to a school kid, it seems like the two most significant factors are a) the angle of attack during take-off - like pac

If you want to satisfactorily explain this to a school kid, it seems like the two most significant factors are a) the angle of attack during take-off - like packing the air under the wing while creating a vacuum above it and b) the curvature taking over the job of "vacuum creation" during steady flight. A flat-wing plane with its wings slicing the air won't have any lift in steady flight. The only way for such a wing to get lift is to use some angle of attack. The lift on a curved wing is enough to support its weight when flying fast, but too subtle to literally lift the plane way up starting from lower speeds as on the ground. Does that about capture the essence of it? Invoking the Coanda effect seems somewhat unnecessary. For example, if you have a wing fitted with zillions of tiny holes through which a small amount of air is being constantly ejected (to counteract the Coanda effect), it still seems (in my mind) possible for the wing to get lift using the angle of attack and curvature.