Older iPads are missing a critical screen hardware layer that is needed for an Apple Pencil to work.
Apple is never going to create a stylus that is going to work with its older, aging iPads.
So, you can forget that possibility.
Have you tried any third party smart Bluetooth stylii with your iPad Air 2?
The ONLY third party stylus that I can truly and honestly recommend you try with your iPad Air 2 is the Adonit Pixel.
http://www.adonit.net/jot/pixel/
It works with approx. 30 of the most popular drawing and notes apps.
Purchase directly from the Adonit website to ensure you get a stylus with the most up to date stylus firmware.
Good Luck to You!