fitness plus on MacBook

MacBook Air does not support Fitness+. An iPad Air (3rd or 4th) or other iPad would work, among other choices.

https://www.apple.com/apple-fitness-plus/

Apple Fitness+ requires Apple Watch Series 3 or later with watchOS 7.2 or later and one of the following Apple devices: iPhone 6s or later with iOS 14.3 or later, iPad with iPadOS 14.3 or later, or Apple TV with tvOS 14.3 or later.

With watchOS 7.3 or later and iOS 14.5 or later, Fitness+ users can stream audio and video from Fitness+ workouts to AirPlay 2–enabled TVs and devices. However, metrics like timers, heart rate, and Activity ring celebrations will only be visible on Apple Watch. And the final Burn Bar position will only be displayed in the workout summary on Apple Watch.

If the MacBook Air was purchased from Apple in the last 14 days, it can be returned for a refund.

MacBooks were discontinued over 2 years ago. Please identify the exact model of your Mac.

Please read: https://discussions.apple.com/docs/DOC-5931

The last time I checked, iPads, iPhones, and Apple Watches are Apple products. They run iOS, not macOS.

Not feasible to exercise with a MacBook Air hanging from your neck.