RNAS Ballyhalbert (later HMS Corncrake) was an airfield near Ballyhalbert, in North (County) Down, Northern Ireland during the Second World War, used by the Royal Air Force in the defence of Belfast and, later, by the Royal Navy, when it was a naval air station commissioned as HMS Corncrake.Aircraft types using the airfield included the Supermarine Seafire, and airmen from Australia, New Zealand and Poland were based there.