Do I need added security for my MacBook Air?

See the articles Set up your Mac to be secure - Apple Support

Security features on your MacBook Pro - Apple Support

Apple Platform Security - Apple Support

Change Security & Privacy General preferences on Mac - Apple Support

Protect your Mac from malware - Apple Support

Uninstall Norton Install and uninstall apps from the Internet or disc on Mac - Apple Support

You don't need Norton Security for a Mac.

Apple has built-in protection against those things. 😉

I'm always getting notifications from Norton Security and others saying I need this.

Those things are scams. Ignore them.

Apple offers plenty of built-in security. You can augment it by following these recommendations:

Set up your Mac to be secure - Apple Support

Protect your Mac from malware - Apple Support

Security features on your MacBook Air - Apple Support

For a technical overview of macOS's built-in protections, read Protecting against malware in macOS - Apple Support

To learn more about how to protect yourself from succumbing to scams, read Effective defenses against malware and other threats