After looking through the available Stack Exchange sites, this one seems to come closest to the appropriate place to ask...
Popular opinion, including my own, is that banning flights to and from the Ebola-ridden portion of Africa would protect us overall. I understand it would increase pressure on that region, making it more chaotic and less conducive to tracking people, so that eventually it could "explode uncontrollably" out of that region in a year or whatever time frame. Sanjay Gupta explains this briefly in Jon Stewart's (at points hysterical) report.
The disadvantage of allowing free travel to and from these regions, as I see it, is that the disease spreads much much faster, and to many many more disparate locations. This is because of the variety of places where each passenger comes from. And also the flight crew and plane itself, which affects all future passengers.
I'd appreciate more educated opinions. I'm far from it, regarding these issues, as are many Americans.