There are at least two flight schools that I know of at Concord airport. I fly for Ram Air and I am currently based out of JQF. If you have the opportunity to hang out with some of the nascar guys, it could lead to a really good flying opportunity down the road.
You should also check out Rock Hill Aviation. They are located at Rock Hill airport which is about 15 miles south of Charlotte. I instructed there for about 2 years. Right now they need a few instructors. The last time I was there they had a few part timers and only one full timer. There is also Wilgrove airport and Goose Creek airport just to the east of Charlotte.
I am a flight instructor at one of the flight schools at JQF.
with fly carolina you will probably meet the most people for networking for later jobs. Paramount flight school will probably give you the most twin time out of the two. FLY CAROLINA doesn't have a twin on the field at JQF>