3D model moving method

I wondered for what does those "glScale,glRotate,glTranslate" are really good for? I will explain. Let say you are making an aircraft simulator. You can move those aircraft with the gl.. functions, but those don''t really change the aircraft vertex info, so in fact, the aircrafts are moving only on the screen, but their X,Y,Z data stay the same. If you want to update the models data (to calculate an aerial battle and so on...), you need to take those x,y,z points and multiply them with the current MODELVIEW matrix... so you actually did the same operation twice! Can''t I just calculate the moving,scaling,rotating by myself, and let opengl just draw the model according to their updated (by myself) data ? Please respond to: preshel@mailcity.com