What a shame. You can't air layer unless the vine is still attached. I'd cut it into smaller sections and try rooting those. I'd use rooting hormones and maybe use perlite to set the cuttings in. God luck.

Thanks I made a few currings with root hormone and Cirkon.

It may be a long shot but worth a try.

Success!
I tried cuttings and Air Layering and the Air Layer worked. Since the vine was severed, I cut a section that still had green under the bark and put the end of it in a bucket of water.
Then I made two wounds, added root hormone, Cirkon and sphagnum moss. About 4 days ago, the roots were well established. I cut two plastic pots added some potting mix and will let the roots fill that container before cutting it off and transplanting.

Great to hear! Thanks for the update.

How is your plant doing now?