In which city are the headquarters of the multinational defence, security and aerospace company, one of the world's largest and ranked 3rd based on revenues in 2015, which has the subsidiary British Aerospace? 
British Aerospace 146: The British Aerospace 146 (also BAe 146) is a short-haul airliner and a regional airliner that was manufactured in the United Kingdom by British Aerospace, later part of BAE Systems. BAE Systems:  Its headquarters are in London in the United Kingdom and it has operations worldwide.
i don't know