You may experience a bug where the audio is stuttering if your Windows version is Windows 10 version 10.0.18362.86 / Windows Version 1903 (May 2019 Update)
Make sure your version of Windows 10 meets the requirements
Microsoft Flight Simulator is developed for Windows 10 Version 1909 or higher. To find out what version is installed on your PC, type "About" in the windows search bar and open the "About your PC" menu. Alternatively, go to Settings > System > About. If your version of Windows is inferior to 1909, make sure to upgrade to the newest version.
You'll find more information about how to upgrade your version of Windows 10, here: