Apple has been designing their own, custom ARM-based chipsets for iPhone and iPad for years. That's led to persistent rumors that Apple might one day move the Mac for Intel to ARM as well, just like they moved it from PowerPC to Intel years go. Whether an ARM-based MacBook Air makes sense — compared to an ARM-based Mac Pro that's harder to imagine — remains and open question. Would it run OS X or iOS? If the latter, would there be an emulation mode for apps? Would it still allow for Windows virtual machines and Bootcamp?

All we have now is rumors, but that's often all we have before Apple makes announcements.