The Army, Navy, and Marine Corps use warrant officers, while the Air Force does not have a warrant officer program. They serve as technical experts and leaders within those branches. There are five grades of warrant officers: W1 (warrant officer), then CW2 through CW5 (chief warrant officer). They are rated above the enlisted personnel, but subordinate to officers. This license plate, I believe owned by a warrant officer, second grade, was seen in Atlanta, Georgia.