Do I need to install separate firmware updates for my MacBook Air?

Regarding the MacBook Air: No, you don’t need to do anything special. Apple bundles all critical firmware fixes—Secure Enclave updates, Thunderbolt vulnerabilities, boot ROM patches—into macOS updates. Just install macOS updates when they appear in System Settings, and you’re covered. The real risk is letting your macOS version get old, so turn on automatic updates or check every couple of months.