He declared at check-in that he had the gun, which is what you're supposed to do, but this is NYC... He should have made himself familiar with their laws first, but this isn't some guy willing to do harm.
Unfortunately, his girlfriend surprised him with a trip to NY, and they packed the gun in a hurry. It was only a problem when trying to check it going from NY back to NC.
NY laws being draconian as they are, he was charged with a loaded gun. Technically, it wasn't loaded, but according to NY, any ammo stored in the same case is considered "loaded".
Unlike Plaxico Buress, he didn't have it physically loaded, nor did he fire it. Hopefully that will make a plea deal a bit easier.