In NC, loaded OC in a car is perfectly legal, as long as the firearm is in PLAIN VIEW.
What constitutes "plain view" is, unfortunately, NOT defined by statute, and is therefore left to the discretion of LEOs...
It is generally accepted that in a holster on your hip while in a car is NOT plain view, and constitutes "concealed carry". This is rationalized by LEOs by saying that when you are in the drivers seat, with a seatbelt on, an approaching officer on the driver's side cannot see your holstered firearm, and therefore it is "concealed".
If you put it on the passenger seat, or on your dashboard, that is "plain view", but you'll still want to notify the officer that you have a firearm in the vehicle. Don't do this by saying "I've got a gun!". Just calmly inform the officer when you hand him your DL and registration that you have a firearm in the vehicle. Depending on where you are, and what you look like, the response can be anything from a "oh, OK..." to getting dragged out of the car, proned on the ground, and having your firearm temporarily seized while they run the numbers "to see if it's stolen"...
Personally, I'd suggest just getting the permit. It makes traveling easier, gives you more flexibility in carry, lets you carry however you want in 38 other states, AND it makes it so you don't have to buy those silly "Handgun Purchase Permits" from your sheriff every tie you want to buy a new firearm from a dealer. And the legal training you;ll get in the class clears up a LOT of the questions we are constantly fielding on this forum about the weirdness and vagueness of NC law.