An AIA file is a project file created by the MIT Inventor App that teaches beginners to create Android and iOS applications. It is saved as compressed ZIP file and can contain many folders and files. These include source files such as BKY, SCM and YAIL that are part of the app project. MIT App Inventor provides an Android emulator that works the same way as an Android but appears on the screen. This helps in testing the apps on emulators.
AIA files are saved to disc in compressed ZIP format. In order to view the contents of this ZIP archive, simply rename the file extension to .zip and you will be able to view the contents of this archive.
MIT App Tutorial
App Inventor provides several tutorials for beginners to develop Android and iOS apps. It allows to drag and drop UI elements such as buttons, images, lists, text boxes, and others for creating a mobile application and program its functionality. The App Inventor .aia project is saved online but can also be downloaded for use on computer.