How many people are flying at any one time?

I am investigating certain myths which seem to have taken root, namely a question of “How many people are flying at any one time?”, which the often repeated there are a million people flying at any one time seems to be the mythical answer.

I would be keen to find out if someone can provide a substantive answer to this query, in such a way that my year 1 undergraduate students in environmental studies can understand it. If you would happen to have a visual which shows the peak and trough of how many people typically fly in a 24 hr period, then that would be even better as it would allow them to understand the flow of flights globally.

I thank you in advance for any info or other sources of information/leads that you might be able to provide.
AND my apologies if this subject has already been discussed - but I could not locate it easily.

My kindest regards

You may be better off trying to work backwards from airport passenger data rather than forwards from the number of aircraft in the air; while you can probably count the aircraft to some extent from ADS-B data, working out the passenger load is going to be tricky.

e.g. … 2011-final
Atlanta @ 92M implies ~275k/day, or about 17000 “in the air” simultaneously involving that airport if you assume 1.5 hour flights evenly spread across the day (which is not going to be true, but…)

1M simultaneous sounds like it’s in the right ballpark at least.

According to this site, they were expecting 3.3 billion people flying during 2014. … 30-01.aspx

Using obj’s calculations which seem pretty reasonable, you get 9 million/day. With an average flight time of 1.5 hours, that would be 9m/16 = 565,000. So for there to be 1 million at any given time, the average flight time would have to be 2 hours and 40 minutes. Which world wide may very well be.

The hard part would be peaks and troughs which are local. Peak in the US is trough time in Asia and vice versa. So it probably evens out over a 24 hour period.