<span class="Apple-style-span" style="font-family: Verdana, Arial; font-size: 13px; -webkit-border-horizontal-spacing: 1px; -webkit-border-vertical-spacing: 1px; ">Rubber bands are to let the wing come off when you hit the ground. Tears up less of the plane in a bad landing. That and less cost of building are why the trainers have them.