There's a couple places that do open houses every now and then, I think.

I remember when I worked the ramp at FedEx, there was a once yearly airshow at OAK, and they would have a couple planes out on display. But that was as close as you could get. Now, are you talking seeing what actually happens behind the scenes? Because there's a few good dvds out there on what you're looking for. Check out http://www.worldairroutes.com/ . Hope that helps!!