Hi
Windows 8.1 Preview should work with the same devices and programs that work with Windows 8. In some cases, the device or program might not work or may require an update, or you might need to uninstall some programs, and then reinstall them after installing Windows 8.1 Preview.
You may also try to install the Microsoft Flight Simulator X in compatibility mode and check if it helps:
a. Right click on setup file.
b. Click on Properties.
c. Click on Compatibility tab.
d. Put a check mark on Run this program in compatibility mode for.
e. Select Windows 8.
f. Put a check mark on Run this program as an administrator under Privilege Level.