Apparently Adobe EOL'ed Air back in 2019. It's been taken over by Harmon/Samsung. You can find it here: https://airsdk.harman.com/ However it is NOT free unless you meet certain qualifications and even then the free version is limited/watermarked/whatever. They do not sell it as once & done software either, no, you must subscribe. Subscriptions start at $199 US per year not including taxes and there is no guarantee it will even work or even install on your flavour of Windows, Mac or Poser, according to all the questions I've seen in the Adobe support community. Looks like the Air forum over there is deserted as none of the recent questions have been answered.