Still not getting hey Siri to work

Support for "Hey Siri" depends on your model of iPad. "Hey Siri" isn't supported on iPad Air 2.

If "Hey Siri" isn't working on your iPhone or iPad - Apple Support

Devices that support 'Hey Siri' - Apple Support

Hey Siri is supported on your iPad Air 2.

You have to connect your iPad Air 2 to power if you want to use Hey Siri.

Newer models can use Hey Siri without plugging in.