My 2017 12" MacBook is starting to show its age, but I hate that there is nothing to replace it right now. There's no reason to get a MacBook Air since it's the same form factor as the 13" Pro. But it seems unlikely they're going to release a small computer again at this point.
All Chromebooks are linux-capable (especially if one gets an x86 one) and there certainly are 11 inch Chromebooks
(and there are slim 13 inch ones like the Galaxy Chromebook and Pixelbook Go)