There are number of old aircraft still flying with passengers, and the Northwest (Delta) DC-9-31 N8920E is really good example of that. Her first flight was in January 1967, now almost 43 years ago. In the UK Loganair is flying Twin Otter to Barra, and one of them will turn 30 next year. If we are talking about petrol props, there are a number of Islanders and Trilanders that have turned 30 and still are in passenger service in the UK. Greenlandair uses de Havilland Canada Dash-7 to fly to a number of STOLport on the island, and the oldest turned 30 last February. In other words, there are a number of really old aircraft flying around with paying passengers. The two oldest aircraft I've flown with both flew for the first time in 1943 - a Dragon Rapide and a DC-3 - and I survied.