There is no single definition of an "aircraft carrier", and modern navies use several variants of the type. These variants are sometimes categorized as sub-types of aircraft carriers, and sometimes as distinct types of naval aviation-capable ships. Aircraft carriers may be classified according to the type of aircraft they carry and their operational assignments. Admiral Sir Mark Stanhope, <answer>former head of the Royal Navy</answer>, has said that "To put it simply, countries that aspire to strategic international influence have aircraft carriers".
Who is Admiral Sir Mark Stanhope?
former head of the Royal Navy