No, people who regularly travel by aircraft do not live longer due to time dilation. While time dilation is a real phenomenon predicted by the theory of relativity, its effects on human life are extremely small and practically negligible in everyday scenarios, including air travel.
Time dilation effects become significant only under extreme conditions, such as when traveling at speeds close to the speed of light or in the presence of extremely strong gravitational fields. For typical commercial aircraft speeds and altitudes, the time dilation experienced by passengers is far too minuscule to have any noticeable impact on their lifespan.
For example, in a transcontinental flight lasting several hours, the time dilation experienced due to the speed of the aircraft would only amount to a fraction of a second when compared to an observer on the ground. Similarly, the difference in gravitational potential between cruising altitude and sea level would also result in a negligible time dilation effect.
Therefore, while time dilation is a fascinating concept in physics, it does not play a significant role in the lifespan of individuals who regularly travel by aircraft. Other factors, such as overall health, lifestyle choices, and genetics, have a much greater impact on human longevity.