Loved the Product. the 4 star over 5 star rating is due to the us of the Diamond Aircraft. It would be helpful is you could highlight all spots that were aircraft specific. I think I got them all as I read through each lesson and tweaked it, but I am sure I may have missed a couple. Several spots you used an airspeed that I would not identify at Vx, Vy, or Va......Overall.... Great Product.