I know - no where near NC, but since someone mentioned San Jose.....

For plane watching - no light GA, but does have biz jets and the
airliners - is MSP. They have a parking area off of Post Road, just
for plane watchers. Never stopped by there when there were less than
three families sitting atop thier car watching the planes go by. The
spot is towards the south end of on of the two parallel runways.

If you want small craft - in the Minneapolis/St Paul area - Crystal
Airport on the north end of the metro and Flying Cloud near the south
end - are usually quite busy, especially on nice weekends.

Randy