I am not able to open airplay on my macbook air

1. AirPlay will not activate unless you have an AirPlay compatible device on the same WiFi Network.
2. You cannot AirPlay between an iPad, MacBook or an iPhone. You can Airplay to an Apple TV device or an AirPlay compatible television.
3. What you are talking about in your post is called the SideCar feature where you extend your MacBook Air's screen to an iPad. The catch here is that only certain iPads and MacBooks work with this feature. Please see this link for more information ➔ SideCar System Requirements.

Axel F.

Are your two devices compatible?

Hi,

Use your iPad as a second display for your Mac.

https://support.apple.com/guide/mac-help/use-your-ipad-as-a-second-display-mchlf3c6f7ae/mac