Yeah,I have not got the nescessary skills to set one up,but basically how it works is you lease your rolling stock until you have earned enough cash to purchase your own.From then on the more journeys you do the more cash comes rolling in.I should imagine it might be a bit more difficult to set up on MSTS because of all the different routes.On MSFS how it works is ,you have a website that you join and setup your company on.The website bank loans you the cash to obtain your Aircraft and from then on you get so much income for each trip you fly less fuel costs etc,etc..The website has a client which links to MSFS to log the journeys that you make and pays you accordingly.Your own bank account and aircraft that you own are also kept on the website.You can also advertise for staff to join your airline on the site.
It just gives you a reason to fly.
Perhaps when MSTS2 is released it might be easier to set up especially if all the UK lines are present and joined up as in real life.
Yours Stan