[essayist]

Peter Senge brought your first point to life for me:

The Wright brothers proved that powered flight was possible, but the McDonnel Douglas DC3, introduced in 1935, ushered in the era of commercial air travel. The DC3 was the first plane that supported itself economically as well as aerodynamically....

The DC-3, for the first time, brought together five critical component technologies that formed a successful ensemble. They were: the variable-pitch propeller, retractable landing gear, a type of lightweight molded body construction called “monocque,” a radial air-cooled engine, and wing flaps. To succeed, the DC3 needed all five; four were not enough. One year earlier, the Boeing 247 was introduced with all of them except wing flaps. Boeing’s engineers found that the plane, lacking wing flaps, was unstable on takeoff and landing, and they had to downsize the engine.

https://www.penguinrandomhouse.ca/books/163984/the-fifth-dis...