Overview: Dr. Lippisch points out the main problems of flight: lift and drag, control and stability, and propulsion. He explains the correlation between flow velocity, the local pressure, and the distance between streamlines. A picture of a light plane in flight is projected into the wind tunnel so that viewers may have a side view of such a plane and the streamlines around it. He explains velocity distribution and demonstrates how increasing speed diminishes the pressure on a surface and vice versa.