Cross platform issue

I build Windows AIR app on a Windows machine or VM
I build macOS AIR apps on a macOS machine or VM
I build Linux AIR apps on a Linux machine or VM

in fact, it's more than that
but basically you can not do it from only 1 machine

VM can work to some extends
but there are also cases where you can not use a VM and need a "real" machine

My main machine is macOS,
if I need to publish an AIR app for Windows 7/8/8.1 and sign it with a certificate
I can't do it from a VM, I need to do it on a real machine

If I need to publish an AIR app for Windows 10 and the publish on the Windows Store
I can do it from a VM, use the Desktop Bridge app there, and test, etc.

Every different operating system have a a little bit of different needs,
but I would argue because you publish to a particular OS target,

then the strict minimum is to be able to run a VM to test your app there

There are no direct work arounds except for the use of virtual machines as far as I know.