How can I get the stop sign away from under the volume of my MacBook Air?

To remove the stop sign icon that appears under the volume control on your MacBook Air, try resetting the NVRAM/PRAM. Shut down your Mac, then power it back on while holding down the Option, Command, P, and R keys for about 20 seconds. If the issue persists, check your System Preferences for any accessibility settings or audio configurations that might be causing the icon to appear. If needed, consider restarting your Mac or updating your operating system.