How to Make Macbook a Slave Display for Raspberry Pi 3b? I need to get displays for my microprocessors which I need for different tasks. I can have a USB-microUSB-HDMI connection to the ultrabook. 
I am using Macbook Air 2013-mid and El Capitan 10.11.4. 



How can you make Macbook a Slave Display for Raspberry Pi 3b.
It's definitely not feasible, and likely impossible. Whatever ports are for video and audio on your MacBook Air would be out, like to an external display, not in. You could possibly disassemble the MacBook Air and spent an absolutely ridiculous amount of time (and maybe money) to maybe get it to work, but really, you just need a separate display.