In Ray Bradbury’s “The Flying Machine,” the underlying themes revolve around the notion of technological advancement in society. Specifically, the story deals with the notion that unchecked technological advancement can have untold and disastrous effects on the "greater good."
The narrative depicts an ancient Chinese emperor, Emperor Yuan, who is a custodian of the Great Wall of China in the year 400. He is a sensible man and acts with logic and reason to provide the greatest good for his country. One day, his servant tells him of a great and wondrous sight: a man flying, like a dragon in the sky. But the emperor is wary when he goes to visit this flying machine's inventor:
"What have you done?" demanded the Emperor.
"I have flown in the sky, Your Excellency," replied the man. "What have you done?" said the Emperor again.
"I have just told you!" cried the flier.
"You have told me nothing at all."
Here, you see the notion of technological advancement and its potential threat to society. To the inventor, the flying machine is a work of beauty and wonder, yet to the Emperor, the machine represents a world of possibilities too unimaginable to predict.
Emperor Yuan knows that invention can be beautiful; it can mean life, liberty, and happiness. But it can also mean death, destruction, and chaos, which the invention of the machine pose. The emperor is an inventor himself, so he knows that it is the inventor's hubris and naivete that are to be feared:
"Here is the man who has made a certain machine," said the Emperor, "and yet asks us what he has created. He does not know himself. It is only necessary that he create, without knowing why he has done so, or what this thing will do."
The emperor’s fears can be justified through the lens of utilitarianism: a form of normative ethics that states that an action is right if it tends to promote happiness and wrong if it tends to produce the reverse of happiness—for all those affected by the action.
Simply put, utilitarianism is doing right by acting in the best accordance with the "greater good." It is this notion that drives the emperor and why, in the end, he decides to take the inventor’s life—because "there are times ... when one must lose a little beauty if one is to keep what little beauty one already has."