# How many people are flying at a given time?

May 26, 2011 6:38 AM Subscribe

How many people are in the air at a given time?

I was on a plane while the Rapture was supposed to be taking place, and it occurred to me: The clouds below me look an awful lot like how heaven is supposed to look. Maybe there are, in fact, exactly 144,000 people in the air right now. Maybe when John of Patmos misunderstood the vision he was given, and he really just saw 144,000 people flying around in airplanes.

Another theory: Revelations specifies that the 144,000 are drawn from the tribes of Israel. According to adherents.com, 0.22% of the world population self-identifies as practicing Judaism. Therefore, if 654,545 are in the air, then 0.22% of them -- or 144,000 -- would be a self-identified practitioner of Judaism. (of course, there are people from the tribes of Israel that probably identified on that survey as "nonreligious". Also, the proportion of these people in the air might not be the same as their proportion in the world).

Anyway, that's the silly version of the question. But it did get me thinking: How many people are in the air at a given time?

Also, it probably depends on the day and time, how many people are flying. What's - like - the max, min, and average?

I was on a plane while the Rapture was supposed to be taking place, and it occurred to me: The clouds below me look an awful lot like how heaven is supposed to look. Maybe there are, in fact, exactly 144,000 people in the air right now. Maybe when John of Patmos misunderstood the vision he was given, and he really just saw 144,000 people flying around in airplanes.

Another theory: Revelations specifies that the 144,000 are drawn from the tribes of Israel. According to adherents.com, 0.22% of the world population self-identifies as practicing Judaism. Therefore, if 654,545 are in the air, then 0.22% of them -- or 144,000 -- would be a self-identified practitioner of Judaism. (of course, there are people from the tribes of Israel that probably identified on that survey as "nonreligious". Also, the proportion of these people in the air might not be the same as their proportion in the world).

Anyway, that's the silly version of the question. But it did get me thinking: How many people are in the air at a given time?

Also, it probably depends on the day and time, how many people are flying. What's - like - the max, min, and average?

*Therefore, if 654,545 are in the air, then 0.22% of them -- or 144,000 -- would be a self-identified practitioner of Judaism.*

Your math is off. It's .22% not 22%. There would have to be 65,454,545 people in the air.

There are about 2.5 billion airline passengers every year [pdf] (obviously many of those are people making multiple flights). That works out to 6.8 million per year, but again many of those will be people flying multiple times per day (e.g. connecting flights). It's an upper bound at least. Point being, there aren't nearly enough to support your theory, it's off by a factor of 10.

posted by jedicus at 7:32 AM on May 26, 2011

I believe the convention wisdom from all sources is that the average daily number of passengers is approximately 2,000,000 and the average in air at any one time is approximately 500,000. I would cite sources but just google it and you'll find any number of supports for it. As i said, its at least the convention wisdom...

i have to admit i really like your theory, at least the idea that the rapture is simply a vision of people flying away into the sky.... nice.

-c

posted by chasles at 7:33 AM on May 26, 2011

i have to admit i really like your theory, at least the idea that the rapture is simply a vision of people flying away into the sky.... nice.

-c

posted by chasles at 7:33 AM on May 26, 2011

Of course, Jews might make up a higher percentage of the flying population than they do of the general population. But I don't think that's going to make up for that order-of-magnitude deficit.

What if we extended it to Jews and Christians? That's about a third of the world population (though, again, probably more of the flying population), and 1/3 of 500,000 is only a bit over 144,000.

posted by mskyle at 7:37 AM on May 26, 2011

What if we extended it to Jews and Christians? That's about a third of the world population (though, again, probably more of the flying population), and 1/3 of 500,000 is only a bit over 144,000.

posted by mskyle at 7:37 AM on May 26, 2011

A back-of-the-napkin estimate:

IATA says there are about 250 billion revenue passenger kilometers per month (i.e. the total number of km flown by paying passengers). Some flyers wouldn't be included in this number, including people on non-commercial/private/general aviation flights, military flights, cargo flights, and airline staff (pilots, flight attendants, etc). So let's round up by 10% to account for these other people, and estimate there are 275 billion passenger km per month.

275 billion passenger km per month is equivalent to about 380 million passenger km per hour. In order to figure out the average number of passengers in the air at once, we need to divide by the average passenger's velocity (km/h). This is because when people are travelling faster, these 380 million km would be completed in less time, meaning fewer people would be in the air.

Figuring out the average passenger's velocity is a problem, since there is a wide variety of possible speeds: airliners like a Boeing 777 cruise at about 900 km/hr, a commuter plane like a Dash 8 might hit 500 or 600 km/hr, and a really small plane like a Cessna 172 might be going at 200 km/hr. Small planes don't carry many people, of course, so the average passenger is going to be on an airliner, probably travelling somewhere between a lower bound of 500 and upper bound of 900 km/hr. For a range like this, a decent point estimate is the geometric mean -- in this case 670 km/hr.

Dividing 380 million passenger km/hr by 670 km/hr, that's approx. 570,000 people in the air at once.

posted by blue mustard at 8:01 AM on May 26, 2011

IATA says there are about 250 billion revenue passenger kilometers per month (i.e. the total number of km flown by paying passengers). Some flyers wouldn't be included in this number, including people on non-commercial/private/general aviation flights, military flights, cargo flights, and airline staff (pilots, flight attendants, etc). So let's round up by 10% to account for these other people, and estimate there are 275 billion passenger km per month.

275 billion passenger km per month is equivalent to about 380 million passenger km per hour. In order to figure out the average number of passengers in the air at once, we need to divide by the average passenger's velocity (km/h). This is because when people are travelling faster, these 380 million km would be completed in less time, meaning fewer people would be in the air.

Figuring out the average passenger's velocity is a problem, since there is a wide variety of possible speeds: airliners like a Boeing 777 cruise at about 900 km/hr, a commuter plane like a Dash 8 might hit 500 or 600 km/hr, and a really small plane like a Cessna 172 might be going at 200 km/hr. Small planes don't carry many people, of course, so the average passenger is going to be on an airliner, probably travelling somewhere between a lower bound of 500 and upper bound of 900 km/hr. For a range like this, a decent point estimate is the geometric mean -- in this case 670 km/hr.

Dividing 380 million passenger km/hr by 670 km/hr, that's approx. 570,000 people in the air at once.

posted by blue mustard at 8:01 AM on May 26, 2011

I've just been travelling through Middle Eastern airports festooned with HSBC ads saying that at any particular time there are 500,000 people in the air. I don't know what the basis for the assertion is but one presumes there is one.

posted by Logophiliac at 8:16 AM on May 26, 2011

posted by Logophiliac at 8:16 AM on May 26, 2011

Flightaware shows about 5-6k airborne flights at any one time. Of course, that varies from large passenger flights to small Cessnas.

You can get more detail on this page which shows flights by aircraft type.

I wont go through the table. But an Airbus can hold about 200 people. So just the Airbus flights is about 100,000 people. So, the above estimates of 500,000 sound about right.

posted by vacapinta at 9:45 AM on May 26, 2011

You can get more detail on this page which shows flights by aircraft type.

I wont go through the table. But an Airbus can hold about 200 people. So just the Airbus flights is about 100,000 people. So, the above estimates of 500,000 sound about right.

posted by vacapinta at 9:45 AM on May 26, 2011

I like it. Thanks for the good info (and sources of info). Also the idea of including Christians, to bring us to near 144,000. Also for correcting my math. We should really send this info to the editors of the Bible. Who is in charge of that nowadays?

posted by Galaxor Nebulon at 9:53 AM on May 26, 2011

posted by Galaxor Nebulon at 9:53 AM on May 26, 2011

This thread is closed to new comments.

posted by The Bridge on the River Kai Ryssdal at 7:30 AM on May 26, 2011