New Macbook Pro 2017 won't boot from USB drive
There are hardware specific builds of the OS that sometimes will run on one computer and not on another (due to drivers that are needed for certain models, etc). So this means that your MB Air setup will likely not work to boot the new MBP.

See here for some info:
https://support.apple.com/en-us/HT204319

For this reason, you want to transfer over your data using the Migration Assistant (you can do this between computers, or using a Time Machine backup).