Duncan, it depends on whether you mean any aircraft type including piddly little ones, or only airliners. Certainly on the airliner side there are still C-46, DC-3, DC-4, DC-6 and even a couple of DC-7s flying commercially - mainly cargo though. Only last year I flew on a DC-3 between Yellowknife and Hay River (Canada) on a scheduled passenger Buffalo Airlines flight. On the smaller side there are still many old examples flying around privately. Too many to name.