When Airplane mode wifi and bluetooth are still turned on. So yes the AirTag will still know it is near its owner. If Airplane mode prevented that then it would also prevent someone to know there was an unknown AirTag near them. And AirTag itself does not have an Airplane mode only the iOS device. Airplane mode now only turns off the cellular radio.When in a plane and in airplane mode, the AirTag does not know it is near its owner.