I had an ASUS that was only marginally thicker than a MPB with upgradable ram and storage (which puts it miles ahead of the MBA I ran out of both on immediately

I had an ASUS that was only marginally thicker than a MPB with upgradable ram and storage (which puts it miles ahead of the MBA I ran out of both on immediately despite using it for almost nothing). The battery was likely also replacable, I just never tried.