Can i use AirTag with airplane mode on?

You can check connection while at home. Put your phone in airplane mode and turn off wifi. I just did that and no AirTag connection. It’s my understanding that Air Tags use Bluetooth to check location.

Thanks Horsewoofie, so I need WiFi and my Blue tooth on to use my AirTag. With airplane mode on , I will need to connect to the public WiFi in the airport.

Per Apple: "Your AirTag sends out a secure Bluetooth signal that can be detected by nearby devices in the Find My network. These devices send the location of your AirTag to iCloud — then you can go to the Find My app and see it on a map. The whole process is anonymous and encrypted to protect your privacy. And itʼs efficient, so thereʼs no need to worry about battery life or data usage."

Make sure your bluetooth service is on, as well as wifi. Airplane mode turns off your cell service and should not affect either wifi or bluetooth.

To use the "Find My" app - to locate your airtag when it's "away" - you will need either cellular or wifi connection to access iCloud and the location.

Thanks TheOrdinaryRebecca, I just tried it at home. With airplane mode OFF BUT Bluetooth ON, the AirTag was able to emit a sound. However the ‘FIND’
with the direction arrow to show where the iPhone is did not work.

I think there are 2 parts to this question.

1. Can you FIND (with the app's guidance) your AirTag with airplane mode on AND bluetooth on/off.
2. Can you TRACK (with the map visualization) your AirTag with airplane mode on AND bluetooth on/off.

Testing in your home where the ONLY apple device nearby is the phone you have in your hand will not be a good representation of the real world. Your bag with a tag will be loaded in the US, and flown (hopefully with you) to your destination, and unloaded and routed through the airport baggage system. During that time, the AirTag is making and losing connections (dozens or more) with all the BT Apple devices it passes along the way - all while you are in airplane mode w/ BT off. The AirTag is sending its unique id to each of those BT devices, and each of those BT devices, if connected to wifi/cellular, are passing that location data to Apple - not you. Presumably, when you get off the plane, you connect to the Apple account (via wifi or cell) and it now can feed you the tracking info from the AirTag. With Bluetooth turned on, if you are down in the luggage area, the AirTag will connect to your phone and then you can find it using the tracking and the pinging.

Seemingly, for the "expected" result of a bag delivered properly to its destination, JUST using BT and no wifi should be sufficient to find the AirTag - ie you walk to baggage claim, turn on BT, and it will pick up the AirTag on the conveyer belt when it gets within range. Only when things go sideways - ie the bag is in France when you are in Germany - would the network be needed to dial in the real location of the AirTag. The AirTag will be pinging all the local Apple BT connections and sending a location, and you need your Find My... app connected to Apple via wifi/cellular to get that data from Apple's tracking.
So, FIND with just BT on works fine in the "good" situation where you are using your phone to wander the baggage claim until the AirTag signal is picked up and you can be led right to your AirTag.
So TRACK requires the wifi/cell connection for your phone, and the AirTag to have some ability to ping nearby Apple BT devices connected to the internet. It may be in a strange airport somewhere, but as long as it gets some chance to phone home, it will.

So basically, in a nutshell, AirTags use Bluetooth, so you do not need either cellular service or wifi for the AirTags to work.

However, to open and use the “Find My” app, you do need cellular data or wifi.

Thank you very much Tom R and Mardee for the detailed explanation. I fully understand now.

Also keep in mind that since it's tech, it's not always right. My travel pal and I both put Airtags in our bags and invariably they show them in different locations, even when we can see them sitting next to each other on the baggage carousel. Sometimes it shows that one bag is still at the departure airport. Fun with toys.

A good reminder Phred l. Thanks!