April 20th, 2016, 07:36
It is all Copyrighted and still falls under the Microsoft Flightsim EULA (as does even the Dove Tail Games FSX-SE version as they have stated themselves).
If the old Alphasim aircraft you want to mess with isn't available for download from the Virtavia freeware page my advise would be stay away from it. Finding copies anywhere else means you are playing with an unsanctioned (and possibly/probably illegally uploaded) copy. You are of course (if your conscience allows) able to manipulate the files anyway you can -- keeping in mind that is what it means when the EULA says don't "reverse engineer, decompile, or disassemble".
But if you do keep it for your personal use but do not upload anywhere (as the EULA further states) because then you involve the host of the file depository. ...