Here in Virginia, anything capable of discharging a projectile is considered a firearm, no matter what the actual method of propulsion is. And considering that, properly pumped up, my old Crossman air pistol can fire a .177 caliber pellet or dart at up to 1000 fps, that’s probably fair.
I’m a little unclear on what the specific offense in this case is. The air pistol was “unsecured” lying in the backseat or window of the car. What action is necessary to acceptably secure it? There was no firearms registration card with it. Is one required for a pellet gun?
No FOID is required for most airguns. Required for all arms using gun powder (ie what most people understand as “firearms”). You also need a permit to purchase in addition to the FOID.
Here in Jersey, a BB Rifle requires the same license as a hunting rifle or shotgun. It’s insane.