Federal Law covers this.
The Firearms Owners Protection Act.
Local Law can't preempt state law even though New Jersey recently tried it by arresting an out-of-state traveler for not having a New Jersey Pistol Permit in an airport with a secured, "checked" firearm .
In the vein of sticking it in the ass, that man will very soon be sticking it in the ass of the State of New Jersey. He should probably retire quite comfortably off of that one.
And continuing on the theme of ass stickings, the Firearms Owners Protection Act- the same bill that allowed us to buy ammo through the mail and protects us from malicious prosecutions when traveling through municipalities with bullshit gun laws, is having it's 20th anniversary.
Sadly, it's a black one as it's the bill best known for totally sticking it in the ass machinegun owners