I don't think it's one, and I honestly think I'm stuck with 128gb for the rest of this mb life. I know you can get an external hard drive or a jet drive small or a storejet 600, but you can't install programs on any of them, as far as I know. I tried to search the web if you could replace the internal hard drive of a 13-inch MacBook Air from 2017, but avaique is the only one that doesn't support it.
I really need the extra space, so I can install some programs I need and 128 gb just doesn't cut. Is my only option really selling this and buying a new one with more disk size?