Douglas DC-3

The DC-3 is the aeroplane that made carrying passengers pay. Before it, airlines lived on mail contracts; after it, an airline could fill 21 to 28 seats and make money on the fare alone. It takes off at 11,431 kg on two piston engines, spans 28.96 m, and thousands were built as the C-47 for the war. Enough are still flying, eighty-odd years on, that Boeing still publishes its ground-handling data.