Time keeping is not one of M$ strongpoint in FS.
there is a payware program out there called realtime that will help in this matter. But if you use slew or change the speed from normal to 2x or higher this will create problems for this software as it will reload the scenery each time you slew or change rates. This program will let you try before you buy as it will only work for a short time without unlocking it.
Other than that I am not aware of any way to fix the problem in FS you only notice it as you fly from zone to zone. I flew form Los angelous to Hawaii and used slew it changed from day to night at least three times

The time I was talking about is the time as you fly say from the east coast to the west coast FS will not adjust the time so when you land in san fran it will not be the correct time. Say if started at 8:00 am in Atlanta and it takes we will say 4 hours to fly to San Francisco it should be 9:00 am not 12:00 pm. But if you go there using the go to airport the time will be correct time for that area. 8) Fs will not make time adjustments as you fly from time zone to time zone. And using slew will really blow its mind as it does not know what the time should be.

im confused.  ive never had a problem with time in FS.  its always right where it should be when i fly.  anyway, i wanted to ask something about the scenery issue brought up earlier(at least i think one was brought up earlier).  would it be so incredibly hard for microsoft to make jetways that are actually the same height as the planes? if they dont want to take the trouble of making sure that AI planes line up with it perefectly, fine i can live with that.  but how come the jetways arent even the right height for ANY of the three default commercial jets? i mean wtf? can someone tell me if its hard or something to do that?