the 310 and the 340, but they are the preeminent example of what society and economy will not tolerate in decades to come - 100 liters per hour of leaded gas to move at most 6 people. A huge carbon footprint for a very small benefit in society's eyes.
So what will people fly instead? The NetJets operation and similar charter operators must be taking over so people are just moving up into King Airs and Small Jets, surely no better in terms of carbon footprint?? So those who can, will move up. Those who cannot afford to move up, will (if they used light aircraft for serious transport) give up because a 172 can't replace a de-iced 310 in terms of reliably, nearly all weather, transport.
Hence my view that there will be a huge gulf between recreational flyers in RV's and those flying around in TBM800s, King Airs.......