The way I do it is load the default flight at the default airport then load the save. Like I use that fighter jet in p3d v4 at that afb then load the 757 and it works fine. That method works in fsx too.
So basically open sim, go to free flight then click the button that loads the fight, once its loaded go to load save screen and load the saved flight. Should work. It does for me.

This method works on all the CS planes I've tested it on. I've tried it on all but the 727.