Hi skilled, forgive me - I am not trying to solve your problem.
I was trying to get you to provide lots of information for the many Experts on this forum, to come along and give you the answer you want.
As well as reading those wiki pages, goto - Board Index -> Support and read the 'red writing'. Post
that information, please.
NB : to have a 'punt' is to guess (or to bet recklessly).
Here is my Commandline Output -
D:\Program Files\FlightGear\bin\Win64\fgfs.exe
--fg-root=D:\Program Files\FlightGear\data
--fg-scenery=D:/Program Files/FlightGear/data/Scenery/EGOD;D:/Program Files/FlightGear/data/Scenery/EDDF-ELLX;D:\Program Files\FlightGear\data\Scenery;D:\Program Files\FlightGear\scenery;D:\Program Files\FlightGear\terrasync
--airport=EGDM
--runway=23
--aircraft=lightning
--control=joystick
--enable-random-objects
--enable-auto-coordination
--enable-horizon-effect
--enable-enhanced-lighting
--enable-ai-models
--enable-ai-traffic
--enable-real-weather-fetch
--enable-clouds3d
--geometry=1024x768
--bpp=32
--enable-rembrandt
--timeofday=noon
--disable-terrasync
--callsign=Porcius
--multiplay=out,10,,0
--multiplay=in,10,,0
--enable-fgcom