Do you know which macbook air you want to upgrade to? Like do you know the new motherboard version?
I would honestly like to say you can based off the size. If you were to get the same size but later mobo, the older case may be able to fit it.
I would also like to say no because newer technology may require certain hadware changes, even the slightest hardware adjustment in a motherboard can make an old case incompatible. I only have the current version you have, but I would really need the new version you want to put in as well.
I honestly say in theory you could, but since I've never done it all I'm doing is looking online and I do not see anything yet. I will keep looking for you but I'd like to lean towards no for now.
EDIT: I meant what is both versions:
Give me current model you have, and model you want to upgrade to