This MacBook air will not take a conventional SSD (such as the Samsung EVO 850 or 950). They are a different blade type of SSD and are very similar to M.2 SSD's.
Apple decided to move the notch on the SSD's (the notch is the cut in the middle of the board where it connects to the logic board (MLB... whatever you wanna call it). Which means if you go out and buy a standard M.2 SSD it wont fit.
I have seen variations in where the notch is in older models and I really hope Apple will conform to standards of the industry rather than just call some variation of a connector a different name.
The good news is YES! You can at least increase the storage capacity of a MacBook air of any year. BUT, you must do your homework to make sure you get the right one.