The chord line goes from the leading edge to the trailing edge so if the aileron goes down, so does the chord line against the relative airflow. The bit of the chord line at the leading edge stays where it is, but the other end stays with the back edge of the aileron.
The big thing to get into your head is that (contrary to popular belief) you are not sucked into the air, you are pushed up from underneath due to the line of least resistance created by the lower pressure above the wing.
It is the difference in thatic pressure above and below the wing that is directly involved with flight, but we cannot affect it directly. Instead, we change the dynamic pressure over the upper surface of the wings, especially in the first quarter, where pressure is decreased the most relative to the lower surface to create the change we need. No movement (of an aircraft) would be necessary were it not for the need to reduce the static pressure on the upper surface of its wings by changing the dynamic pressure.
An ailreon deflected upwards creates a lower angle of attack and therefore less of a lift reaction, and vice versa.
Last edited by paco; 24th Jul 2022 at 11:56.