In December 2001, Washington Post political editor Henry Litchfield West made a startling prediction.

In the year 1800, he noted, people traveled at the rate of about six miles per hour, the rate of a horse-drawn coach.

By the year 1900, human beings were routinely

traveling long distances at a rate of 60 miles per hour, the speed of a steam locomotive

or a fast automobile. That was an order of magnitude over the course of a century.

Extrapolate that forward, West noted, and by the year 2000, human beings might be criss-crossing the American continent at the mind-boggling speed of 600 miles per hour.

People might travel, say, from Washington to Chicago, in 70 or 80 minutes.

This seems incredible, West conceded, but is not more marvelous than it would have seemed in

1800 to suggest that the 40 miles from Washington to Baltimore could be traveled in 40 minutes.

Welcome to the history of the 20th century.

Music Episode 48, The Flight of Icarus.

Henry Litchfield West had called it.

The cruising speed of a passenger jet in our time is just a bit less than 600 miles per hour,

and scheduled commercial flights are available today from Washington to Chicago that are under 90 minutes.

Of course, it takes longer than that to board, but that's another story.

The story of the development of the airplane is complex because a number of scientific

principles had to be worked out and engineering problems solved before the airplane, as we know it

today, became possible.

The man who is sometimes called the father of aviation, Sir George Cayley, was nine years old when Paris saw the first manned balloon flights.

Cayley was British, a brilliant engineer and experimenter, and his notebooks from his

school days show us today

that he was pondering the questions of flight from an early age.

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