I'm guessing that the wings / diffusers are supposed to be slightly different lengths so that it has a gentle turn during the glide. If they are the same, then it will fly straight away.
They are supposed to be the same, and the turn is controlled by the addition of weight. However, I didn't glue my tube on quite straight so it looks like the wings are different lengths.
Not sure why you call the wing tips "diffusers". They are rudders to keep the rocket flying straight on boost and while gliding. To get it to turn, add a very small amount to clay to the end of one wing to cause the glider to tilt to one side. It will then turn while gliding in that direction. Be sure to hand toss the glider before flying to test how much is needed for a gentle turn.
