Stevens Aviation at KGSP (Greenville/Spartanburg, SC) is very pet friendly. They have allowed us to bring our animals into the lobby, walk out on the tarmac to load, though they do require that one of their personnel accompany you initially. We did the NBC Nightly News filming there and they could not have been more interested or helpful. I think every employee played with the dogs in the lobby! Great group of folks. I did not ask about fuel discounts but I will next time!
Update: I helped Jon load 12 pups this morning at KGSP and they granted us special permission to drive to the plane for loading. This really was greatly appreciated since 9 of them were 8 week old pups who had never seen a leash and only one of the three adults knew how to walk on a leash. The fresh cookies are always a nice touch as well