This is a long one, so get ready
An issue which i was long suspecting was present. I recently restarted playing INN to get gold planes and noticed that in a suspiciously small time (like a few days) my total pax at INN grew from around 60k (from months ago when i stopped playing when i unlocked BRI) to currently over 150k. I thought initially this was just because i upgraded INN more but it wasnt.
I put it to the test now.
On the bellow screenshot you can see that at the beggining of my session i had 150614 pax
Then after sending off only a single ATR, BAe and E90 (three planes total) i had 151222 pax
Thats an increase of around 600 pax when the total combined capacity of the three is around 300 pax.
In the end i decided to bulk send off all my planes. Keep in mind i filled the previous three stands again.
I sent off all the onscreen planes.
Aaaand ended up with 154528 pax.
I counted 3Atrs, a BAe, an E90 and 8 A320s, for simplicity sake.
Capacity of all of the 13 planes i sent off was calculated to around 1834 pax. I ended up with an increase of around 3300 pax listed.
Devs hope this was helpfull, hope you liked this mini investigation and sorry for the giant post