That’s not something that’s typically done without purpose-built WiFi routing / relaying hardware. I can imagine it being theoretically possible with the kit you have in an iPhone, but I’m sure nobody’s ever bothered trying to code it up — nor would I expect it to be possible without jailbreaking.
But I’m also perplexed … why would you want to do such a thing?
The most common not-on-a-plane reason you’d do this would be to extend a WiFi network past the physical range of the base station’s antenna, or maybe to extend to a different radio spectrum.
Because otherwise it makes life so much easier for the other devices to simply connect directly to the base station themselves, without any sort of middleman.
If this is a commercial flight you’re talking about, two observations.
First is that, every one I’ve been on, if you pay the fee to connect your phone, they also let you connect a laptop and maybe another device as well as part of the same charge.
Second is that, every single time I’ve paid to connect to in-flight WiFi (as opposed to just using the network to access the same on-board content you would otherwise get from the back-of-the-seat infotainment system), I’ve regretted it. Total waste of money. Speeds so slow that even the Wikipedia mobile version is useless.
Which is to suggest that, even if you did manage to relay the network through your iPhone, you’d be lucky to get through a morse code message.
b&