What is it expressing for most people who sport the confederate flag on their car, on a flag, etc.???

I have lived in NC for four years. I was born and raised in Seattle prior to moving here. I had never in my life seen the confederate flag displayed on a car, or waved as a flag at someone's home. What really are these people trying to say? Are they that proud of southern heritage, or is there a bigger message they are tying to send???