Another major airline is apologizing to one of its customers after she was dragged off a plane--for having a pet allergy. NBC News reports a passenger on Southwest Airlines notified the crew she had a life-threatening allergy to animals. Since the woman didn't have a medical certificate, cabin crew called for her removal. When the passenger appeared to not understand why she was being deplaned, security forcibly dragged her from the aircraft. Witnesses say an officer wrapped his arms around the woman’s chest, dragging her down the aisle.