(By Christina Rexrode and Theoden Janes, crexrode@charlotteobserver.com; tjanes@charlotteobserver.com) A car wreck over the holiday weekend killed three young adults, including one who had served in Iraq and another who planned to be an elementary teacher.The three died Sunday evening when their Nissan Altima ran off a mountain road, went airborne for more than 40 feet and slammed into a tree, the N.C.