UK RAF 3 Sqn. Operation "Palliser" - Unamsil, Harrier GR. Mk. 7. The BAE Systems/Boeing Harrier II (GR5, GR7, and GR9 series) is a second generation vertical/short takeoff and landing (V/STOL) jet aircraft used by the British Royal Air Force (RAF) and, since 2006, the Royal Navy. It was developed from the earlier Hawker Siddeley Harrier and is closely related to the U.S.-built AV-8B Harrier II. Both are primarily used for light attack or multi-role tasks, and are often operated from small aircraft carriers.