well, I don't think Apple's going to be making x86 processors, so then you'd have to invoke an ARM MacBook Air.
arn
That would have to be ARM then. It's not impossible given the performance of Apple's A6 and ARM's Cortex A15 (quad core at high clocks might be able to match the current chips in MBAs, assuming performance scales linearly). My take is that the new platform is simply Haswell, though.
It doesn't "have to be ARM". The same folks predicting platform change are the same ones citing a substantive price cut before the new product is introduced. Those are about equally as dubious taken completely literally.
First, AMD is an alternative if driving the Retina display graphics becomes a higher primary design issue than x86 top speed. ( if gutting CPU performance with ARM is an option, then doing much less of a reduction to AMD would be even more viable. Also lacking would be an ARM GPU solution aimed at 2x pixel count pushing that a Retina MBA 13" would require that would be substantively better than AMD or Intel's solutions on track for the same timeframe. )
Second, "platform" could be loosely be used here as changing from two chip solution (CPU + IOHUB) to a single SoC ( system on a chip) solution. Haswell will have SoC, single chip, options.