Basically, accessing the options (esc key) menu In-flight should NOT pause game or flight this especially ruins immersion with online gameplay especially on networks like VATSIM or IVAO.
If one wants to quickly adjust a graphic setting while in flight, the change is done on the go anyways so the game/flight should not be paused.
So, you fly second dickie to an autopilot in an airborne bus at 30,000’ then 
. If you are hand flying an X Cub through the mountains at 1500’ or a Hawk T1 through the Mach Loop at 400kts, you can not afford to take your eyes off the plot for more than routine scans or you get a big headache. So, to leave the aircraft to its own devices while you go ‘tweek’ a setting really wouldn’t work would it?
There should be another key to pause flight if you wanna do that. If you are hand flying a Hawk and can’t afford to take your eyes off , you simply don’t press Esc to change an option or pull up into the clear, level off and do what you gotta do. If you really need to pause gameplay you hit another key and then open the options. But anyway, being paused mid flight online doing so just to change a sound level or such is kinda silly, Pause and Options should be 2 different keystrokes.
Horses for courses I guess, but I could live with that.
It has never been a problem for ages in vatsim if someone enters the menu for a moment or two. What IS a problem though that MSFS doesn‘t have a real pause AT ALL, whatever you do it will never stop the sim and for example fuel flow.
fully agree there should be an option to let us choose
When I fly on VATSIM, and I need, mid-flight, to change a binding or another setting, pausing the sim will freeze the aircraft in the air, which for other pilots and controllers is disturbing and unrealistic.
I totally agree
Henri