DC-3

Two things I left out of my earlier post:

The DC-3 was the very first airliner that could make a profit flying passengers. Up to that time, airlines depended on mail contracts to make money, which is why, when FDR told the Army Air Corps to carry the mail in 1934, the airlines shut down.[1] Both before and after the Army Mail Fiasco, airline pilots were also, in essence, postal handlers and they carried guns in their flight bags.[2] Airline routes were often designated by their airmail designation; anyone who has ever read "Fate is the Hunter" will be familiar with AM-21. If the Post Office didn't have an airmail contract between cities, the airlines didn't fly there. That all changed with the DC-3.

Second, the DC-3 will probably be the first commercial aircraft to make it to 100 years of revenue service. The DST went into service in June, 1936 and the DC-3 followed three months later. Of the airplanes to follow it, the only ones that might make it could be the C-46 and the DC-6, both of which are still in commercial service, or possibly the An-2. But that's probably unlikely for any of them other than the DC-3.

You have to wonder what Donald Douglas and C.R. Smith would have thought if they knew that the airplane they conceived of would fly for a century.

[1]The Army's carrying the mail, incidentally, was a case where the propensity of the generals to say "yes, sir" got a number of young and rather inexperienced pilots killed. The only benefit to the Army was that the whole messy affair pushed the Army Air Corps to get much better at night and instrument flying.

[2]Without all folderol and nonsense of current times. You may speculate what might have happened six years ago if that was still the practice.