GTA SA - Freefall Mission, better way to catch the plane?
The Shamal is faster than the airplane you're given. To counter that, pay attention to the minimap (or open the world map), and predict where the Shamal is heading (it will not go always in a straight line).
This allows you to get closer to it , until you're right on top of it, and flying through the Corona is simply a matter of adjusting your position slightly. Ideally you should keep your height high since descending is easier than ascending.
Once again, the trick is don't follow the plane, intercept it.