>>2341056Figured out what was missing: Air checks the date. The date needs to be faked as in the past for Air to accept the installation. Sounds like something to do with signing.
With a program called "RunAsDate", running airappinstaller.exe, with the date faked to 2010, and the .air file being the parameter, it installed just fine. Might be able to set the Linux time to the past (faketime doesn't work), but this is painless enough now.