After two days of ownership I decided to rip open my new MPA and see if the 2017 had the same ssd as the 2015.
Yes it does!
I ordered this adapter: https://www.amazon.com/gp/product/B073GVNPR2/?tag=macforums0e4-20
and this OEM SSD from Asus laptops: https://www.amazon.com/gp/product/B00VELD92U/?tag=macforums0e4-20
Theoretically I can get twice the speed with this compared to the SSD already in the MacBook Air.
Will report back Sunday to see if this works.