Probably double when you’re on an airline owned by a country that has the death penalty for homosexuality [0] and doesn’t have due process for non-citizens.
[0] https://en.wikipedia.org/wiki/Capital_punishment_in_the_Unit...
Airplane WiFi isn't expensive just because. The more people are on it and the more people exploit it, the shittier it becomes for everyone. It gets drastically worse when flying over water, because ATG (air to ground) transmission isn't possible, and they have to rely on satellite connection exclusively.
The only real solution for in-plane WiFi would be to allocate more frequency space for the purpose. Until that happens, we're doomed to the current situation.
I find reverse-tethering quite useful when the WiFi provider limits access to one device at a time. With iOS devices I also have the option to use my Mac‘s connection over USB.