How do I track an AirTag?

maybe

the airtags only means of communication is bluetooth so it has a range of around 30meters

the airtags do not have gps or the likes so they have no idea of their location

it works if they are within bluetooth range of an iphone with bluetooth enabled and that has a internet connection, they will piggypag that iphones gps location on a message it gets the iphone to send to your apple account.

if your kids airtag is outside of range of a such iphone then the airtag will be dead in the water.

Keep in mind that AirTags are designed to locate your misplaced objects in non-real time.

i.e. Objects which don’t move AND are often in close proximity to other iPhones. (one reason generally they work VERY well at home, in airports, and in office environments)

A moving AirTag — or relatively few iPhones —complicates this task and performance suffers.

No phones - or no cell phone coverage - renders them unlocatable.

For tracking, you have basically two options:

1. Provide your child an iPhone, if they don't already have one. However, most schools do not allow them in the classroom so you may need to check with his school beforehand.
2. Get a dedicated GPS tracking device. They make this for pets, but there shouldn't be a reason why it could not be used with people.

How to add an AirTag to Find My - Apple Support

Set up the AirTag using the instructions in the link above. You will then use the Find My app on your iPhone to locate the AirTag.