I don't think Adobe AIR (the runtime) appears under the Applications menu. Are you referring to the program that isn't compatible with the latest version of AIR?
It might be worth deleting the preferences for AIR and/or the program you want to run. One of those settings is telling you that a newer version is installed.
You should be able to find the "Adobe AIR Uninstaller" in the /Applications/Utilities folder. Just double-click it to start the uninstall process.
Have you ever tried that yourself?
Some googling lead me to this: Uninstalling Adobe AIR on Mac OS X · GitHub
It simply does not work as expected. It does not work as documented. And it does not work as you wrote.
Sorry, for this rant, but this uninstaller must never have been tested.
Yes, I've done this a few times over the last 5 or 6 years In fact, I just did it a minute ago and it worked as expected. I did the following steps:
1. Navigated to the /Applications/Utilities folder and double clicked the "Adobe AIR Uninstaller"
2. Accepted the dialog that told me that AIR 24 was going to be uninstalled (and showed me what applications would be affected)
3. Once the uninstall was done, I navigated to the AIR Archive page and downloaded an old version of AIR (v16 to be exact) - Find and download archived versions of Adobe AIR SDK
4. Ran the installer and installed AIR 16
What version are you trying to install? Is there a reason why you need the old version?
how do you do on windows?
Go to Control Panel\All Control Panel Items\Programs and Features you will find Adobe AIR, right click on the same and click on uninstall.