If you rename the aia file to zip, you can open it. Mine shows the following ( the [_] represents a folder:
[_] assets
|_ {objects used such as images, etc}
[_] src
|_ [_] appinventor
| |_ [_] {appinventor account name}
| |__ [_] {project name}
| |__ {3 objects of each screen}
[_] youngandroidproject
|__ ≡ project.properties
I'm not sure how far this will get you. If anyone can further this into something more useful, please share.