By Dale DenwaltStaff writer ddenwalt@oklahoman.comForget the school desks and old-school chalkboards, this classroom can fly.Forget the school desks and old-school chalkboards, this classroom can fly. Oklahoma CareerTech on Thursday unveiled a retired MD-80 aircraft donated by American Airlines late last year that will be used by students who are learning how to maintain, repair and overhaul aircraft. The aircraft is the newest addition to the Metro Tech Aviation Campus at Will Rogers World Airport, where it will sit alongside small propeller-driven aircraft and an aging DC-9 passenger jet. Ben Robinson, a former U.S.