A different route can affect your flight time, and fuel used on the trip therefore making you either late or early in time. It doesn't affect the small trips as much, but further distanced trips it affects quiet heavily. Even though these routes are the Realistic Routes.
What I believe should happen is that when the pilot is selecting the flight they get another option after the flight and aircraft is picked, and that is the route they wish to take, being either direct, Jet aircraft route, or prop route. Then once they select that in their flight plan it lists the way points. And the flight time is adjusted to suit the distances. These routes could either be added by the admin staff, or when the airlines are adding their flights in another thing they could enter is the possible routes.
The real life routes are quit easy to find and there are a number of websites around to find them. Some websites are:
- http://www.simroutes.com/
- http://vatpac.org/assist/?pg=atcassist
- http://vatpac.org/assist/index.php?pg=pilotassist
- http://rfinder.asalink.net/free/
- http://www.fltplan.com/
This would add another realistic aspect to the flights, and assist with users who use other programs along with FSAirlines like VATSIM for a Virtual Air Traffic Control Network which require realistic routes.
Another aspect that could be added after that would be SID's (Standard Instrument Departure) and STAR's (Standard Arrival Route).