Delete MSFT OFFICE 2011 from MacBook Air

See the following from Microsoft Support https://support.microsoft.com/en-us/office/uninstall-office-for-mac-eefa1199-5b58-43af-8a3d-b73dc1a8cae3#ID0EBBD=Office_for_Mac_2011

Uninstall Office for Mac 2011

Note: You must be signed in as administrator to do these steps, and you probably already are, if you're using your own Mac. If you're at a Mac that's part of a network at work, you might have to ask someone in your IT organization for help with signing in as administrator.

Remove the Microsoft Office 2011 folder

1. Open Finder > Applications
2. Find and then drag the Microsoft Office 2011 folder to Trash.
3. Restart your computer.

As the article stated, you probably are an administrator.

You can go to Apple menu > System Preferences > Users & Groups and look in the sidebar on the left of that Preferences window to see if your username has the word "Admin" under it.