# Airplane Approximation

“What percent of humans who have ever lived on earth have flown in an airplane?”

Raw Responses
0.005%, 0.01%, 0.05%, 0.35%, 0.325% – 0.442%, 1%, 20%, 20%, 20%, 29.4%, 40%

Brett Atkinson (0.35%)
Estimate that there have been around 110,000,000,000 humans in the history of humanity. If that is the case, then with 7,000,000,000 people alive today, then the current population makes up about 6.5% of humans ever. Using 5% of today’s population as the number of people who have flown, plus a small number for those who have died post-invention of the airplane, you come up with a tiny percentage a little more that one third of a percent.

Julian Morris (0.325% – 0.442%)
Number of people who have ever been born- 107,602,707,7911
Number of people in 2011- 6,987,000,0001
Number of people in 1950- 2,516,000,0001

Percentage of people who have flown on the airplane in 2004 – 5%2

I will assume here that 5% of the people in 1950 and 2011 have flown, and that all of those people that traveled back in 1950 are now dead. Not true at all, but it’s gonna get me some numbers.

Percentage of people who are alive in 2011 who have flown:
Percentage of people who have flown overall:

So my best guess is that the percent of humans who have ever flown in an airplane is between 0.325% and 0.442%.

[1] http://www.prb.org/Publications/Articles/2002/HowManyPeopleHaveEverLivedonEarth.aspx
[2] http://www.worldwatch.org/node/4346

Sanjoy Mahajan (1%)
The part that I was most interested in is “how many people have ever lived?” Here is a rough estimate.

Maybe 20,000 years ago, there were maybe a few thousand people (early humans wandering out of Africa). Thus, world population has multiplied by 10^6 in 20,000 years. That’s 20 doublings in 20,000 years, or 1000 years per doubling. As a rough approximation to this somewhat exponential growth, I’ll just pretend that human population was zero until 1000 years ago, when it instantly jumped to the present value of 7 billion.

1000 years is about 14 life expectancies, so the number who ever lived in the 1000 years is 14 * 7 billion or about 100 billion.

For the fraction who have ever flown, most flying has happened in the last 40 years. A large fraction of Americans have flown, and maybe many Western Europeans (though they have decent trains, so don’t need to fly so much). Maybe 1 billion have flown.

Thus, my estimate is 1 percent of humans who ever lived have flown.

Meg Lidrbauch (0.005%)
There have been loads of people on planet Earth since the start of man. I don’t know the exact number, but it’s very large. I feel like a sizable percentage of the people who fly today fly for business, with just a small percentage representing first-time fliers. Then there’s a significant percent of the world’s population (I’m thinking of Africa, mainly) who don’t have access either monetarily or locationally to an airplane.

Next Month
“How many mirrors were broken on the most recent Friday the 13th?”

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