Although this airport calls itself an "international" airport, there is not much to this place other than a couple gates that handle very small planes. This is by my definition a "regional airport" although I guess because of the BMW plant, it may have direct flights once in a while to Germany (most likely non-commercial).
I flew into GSP on a "puddle jumper" American Eagle flight which holds 55 people, and it was smooth sailing. I was on the ground and out to my rental car in less than 10 minutes. Very convienent method of getting to this part of the country!
Airlines servicing GSP:
American Airlines (American Eagle) to DFW or Chicago
Continental (Cleveland, Newark, and Houston)
Delta (Atlanta, New York, Cincinatti)
NWA (Detroit and Memphis)
United (Washington DC and Chicago)
US Airways (Charlotte, NYC, Philly, Washington DC)
A small airport. Thanks to BMW, they have the longest runway in South Carolina.
Plenty of mainline & commuter service. Most common direct destinations are: Atlanta, Washington DC, Orlando, Cincinnati and Dallas.
The Greenville Spartenburg Airport boasts the one of the longest runways in the United States. Most major airlines or their commuter airline affiliates serve the airport. It's a pleasant building, but nothing special. There are not too many restaurants (maybe only one) so one may bring food with them if they have a long wait.
As with most places in the United States, a car is a necessity to see the city.